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15道九年级一元二次方程计算题
1、解方程：x2—2x—1＝0．
2、解方程：
3、解方程：x2＋x－ ＋1＝0．
4、解方程：
5、 用配方法解方程：
6、解方程：3 ( x - 5 )2 = 2 ( 5- x )
7、解方程： ．
8、
9、解方程：(x -1)2 + 2x (x - 1) = 0
10、解方程： .
11、用配方法解方程： 。
12、解方程： ．
13、解方程：x2－6x＋1＝0．
14、用配方法解一元二次方程：
15、解方程： ．
参考答案
一、计算题
1、解：a=1,b=-2,c=-1
B2-4ac=(-2)2-4*1*(-1)=8
X=
方程的解为x=1+ x=1-
2、原方程化为
∴ ，
3、解：设x2＋x＝y，则原方程变为y－ ＋1＝0．
去分母，整理得y2＋y－6＝0，
解这个方程，得y1＝2，y2＝－3．
当y＝2 时，x2＋x＝2，整理得x2＋x－2＝0，
解这个方程，得x1＝1，x2＝－2．
当y＝－3 时，x2＋x＝－3，整理得x2＋x＋3＝0，
∵△＝12－4×1×3＝－11＜0，所以方程没有实数根．
经检验知原方程的根是x1＝1，x2＝－2．
4、解：移项，得 配方，得
∴ ∴
（注：此题还可用公式法，分解因式法求解，请参照给分）
5、）解：移项，得x2 +5x=－2，
配方，得
整理，得（ ）2=
直接开平方，得 =
∴x1= ，x2=
6、解：
7、解：
∴ 或
∴ ，
8、
9、解法一：
∴ ，
解法二：
∵ a = 3，b = 4，c = 1
∴ ，
10、解： - -两边平方化简，
两边平方化简 . --
解之得 ---
检验：将 .
所以原方程的解为 -
11、解：两边都除以2，得 。
移项，得 。
配方，得 ，
或 。
， 。
12、解：方程两边同乘以 ，得
整理得
经检验 ， 都是原方程的根．
13、解法1：x2－6x＋1＝0
∵ b2－4ac＝(－6)2－4＝32
∴ x＝
＝3±2 .
即x1＝3＋2 ，x2＝3－2 .
解法2：x2－6x＋1＝0
(x－3)2－8＝0
(x－3)2 ＝8
x－3＝±2
即x1＝3＋2 ，x2＝3－2 .
14、 解：移项，得
二次项系数化为1，得
配方
由此可得
15、解法一：
解法二：
（1）(3x+1)^2=7
解：(3x+1)^2=7 ∴(3x+1)^2=7 ∴3x+1=±√7(注意不要丢解) ∴x= (±√7-1)/3
（2）9x^2-24x+16=11
解： 9x^2-24x+16=11 ∴(3x-4)^2=11 ∴3x-4=±√11 ∴x= (±√11+4)/3 ∴原方程的解为x1=(√11+4)/3 x2=(-√11+4)/3
(3) (x+3)(x-6)=-8
解：(x+3)(x-6)=-8 化简整理得 x^2-3x-10=0 (方程左边为二次三项式，右边为零) (x-5)(x+2)=0 (方程左边分解因式) ∴x-5=0或x+2=0 (转化成两个一元一次方程) ∴x1=5,x2=-2是原方程的解。
(4) 2x^2+3x=0
解：2x^2+3x=0 x(2x+3)=0 (用提公因式法将方程左边分解因式) ∴x=0或2x+3=0 (转化成两个一元一次方程) ∴x1=0，x2=-3/2是原方程的解。 注意：有些同学做这种题目时容易丢掉x=0这个解，应记住一元二次方程有两个解。
(5) 6x^2+5x-50=0 (选学）
解：6x2+5x-50=0 (2x-5)(3x+10)=0 (十字相乘分解因式时要特别注意符号不要出错) ∴2x-5=0或3x+10=0 ∴x1=5/2, x2=-10/3 是原方程的解。
(6)x^2-4x+4=0 （选学）
解：x^2-4x+4 =0 （∵4 可分解为2 ·2 ，∴此题可用因式分解法） (x-2)(x-2 )=0 ∴x1=2 ,x2=2是原方程的解。
(7)（x-2）^2=4（2x+3）^2
解.(x-2)^2-4(2x+3)^2=0. [x-2+2(2x+3)][(x-2-2(2x+3)=0.
(5x+4)(-5x-8)=0.
x1=-4/5, x2=-8/5
（8）y^2+2√2y-4=0
解(y+√2)^2-2-4=0.
(y+ √2)^2=6.
y+√2=√6.
y=-√2±√6.
y1=-√2+√6；
y2=-√2-√6.
（9）（x+1）^2-3（x+1)+2=0
解(x+1-1)(x+1-2)=0.
x(x-1)=0.
x1=0,
x2=1.
（10）x^2+2ax-3a^2=0（a为常数）
解 (x+3a)(x-a)=0.
x1=-3a,
x2=a.
(11)2x^2＋7x＝4．
解：方程可变形为2x^2＋7x－4＝0．
∵a＝2，b＝7，c＝－4，b2－4ac＝72－4×2×(－4)＝81＞0，
∴x＝ ．∴x1＝ ，x2＝－4．
(12)x^2－1＝2 x
解：方程可变形为x^2－2 x－1＝0．
∵a＝1，b＝－2 ，c＝－1，b2－4ac＝(－2 )2－4×1×(－1)＝16＞0．
∴x＝ ．∴x1＝ ＋2，x2＝ －2
（13） x^2 + 6x+5=0
解：原方程可化为(x+5)(x+1)=0
x1=-5 x2=-1
(14) x ^2－4x+ 3=0
解：原方程可化为(x-3)(x-1)=0
x1=3 x2=1
(15)7x^2 －4x－3 =0
解原方程可化为 (7x+3)(x-1)=0
x1=-3/7 x2=1
(16)x ^2－6x+9 =0
解原方程可化为
(x-3)^2=0
x1=x2=3
(17)x²+8x+16=9
解：(x+4)²=9
x+4=3或x+4=-3
x1=-1,x2=-7
(18)(x²-5)²=16
解：x²-5=4或x²-5=-4
x²=9或x²=1
x1=3,x2=-3,x3=1,x4=-1
(19)x(x+2)=x(3-x)+1
解x²+2x=3x-x²+1
2x²-x-1=0
(2x+1)(x-1)=0
x1=-1/2 x=1
(20) 6x^2+x-2=0
解原方程可化为(3x+2)(2x-1)=0
(x+2/3)(x-1/2)=0
x1=-2/3 x2=1/2
这是20道有过程的，还有一些没有过程，只有答案的。
1)x^2-9x+8=0 答案：x1=8 x2=1
(2)x^2+6x-27=0 答案：x1=3 x2=-9
(3)x^2-2x-80=0 答案：x1=-8 x2=10
(4)x^2+10x-200=0 答案：x1=-20 x2=10
(5)x^2-20x+96=0 答案：x1=12 x2=8
(6)x^2+23x+76=0 答案：x1=-19 x2=-4
(7)x^2-25x+154=0 答案：x1=14 x2=11
(8)x^2-12x-108=0 答案：x1=-6 x2=18
(9)x^2+4x-252=0 答案：x1=14 x2=-18
(10)x^2-11x-102=0 答案：x1=17 x2=-6
(11)x^2+15x-54=0 答案：x1=-18 x2=3
(12)x^2+11x+18=0 答案：x1=-2 x2=-9
(13)x^2-9x+20=0 答案：x1=4 x2=5
(14)x^2+19x+90=0 答案：x1=-10 x2=-9
(15)x^2-25x+156=0 答案：x1=13 x2=12
(16)x^2-22x+57=0 答案：x1=3 x2=19
(17)x^2-5x-176=0 答案：x1=16 x2=-11
(18)x^2-26x+133=0 答案：x1=7 x2=19
(19)x^2+10x-11=0 答案：x1=-11 x2=1
(20)x^2-3x-304=0 答案：x1=-16 x2=19
(21)x^2+13x-140=0 答案：x1=7 x2=-20
(22)x^2+13x-48=0 答案：x1=3 x2=-16
(23)x^2+5x-176=0 答案：x1=-16 x2=11
(24)x^2+28x+171=0 答案：x1=-9 x2=-19
(25)x^2+14x+45=0 答案：x1=-9 x2=-5
(26)x^2-9x-136=0 答案：x1=-8 x2=17
(27)x^2-15x-76=0 答案：x1=19 x2=-4
(28)x^2+23x+126=0 答案：x1=-9 x2=-14
(29)x^2+9x-70=0 答案：x1=-14 x2=5
(30)x^2-1x-56=0 答案：x1=8 x2=-7
(31)x^2+7x-60=0 答案：x1=5 x2=-12
(32)x^2+10x-39=0 答案：x1=-13 x2=3
(33)x^2+19x+34=0 答案：x1=-17 x2=-2
(34)x^2-6x-160=0 答案：x1=16 x2=-10
(35)x^2-6x-55=0 答案：x1=11 x2=-5
(36)x^2-7x-144=0 答案：x1=-9 x2=16
(37)x^2+20x+51=0 答案：x1=-3 x2=-17
(38)x^2-9x+14=0 答案：x1=2 x2=7
(39)x^2-29x+208=0 答案：x1=16 x2=13
(40)x^2+19x-20=0 答案：x1=-20 x2=1
(41)x^2-13x-48=0 答案：x1=16 x2=-3
(42)x^2+10x+24=0 答案：x1=-6 x2=-4
(43)x^2+28x+180=0 答案：x1=-10 x2=-18
(44)x^2-8x-209=0 答案：x1=-11 x2=19
(45)x^2+23x+90=0 答案：x1=-18 x2=-5
(46)x^2+7x+6=0 答案：x1=-6 x2=-1
(47)x^2+16x+28=0 答案：x1=-14 x2=-2
(48)x^2+5x-50=0 答案：x1=-10 x2=5
(49)x^2+13x-14=0 答案：x1=1 x2=-14
(50)x^2-23x+102=0 答案：x1=17 x2=6
(51)x^2+5x-176=0 答案：x1=-16 x2=11
(52)x^2-8x-20=0 答案：x1=-2 x2=10
(53)x^2-16x+39=0 答案：x1=3 x2=13
(54)x^2+32x+240=0 答案：x1=-20 x2=-12
(55)x^2+34x+288=0 答案：x1=-18 x2=-16
(56)x^2+22x+105=0 答案：x1=-7 x2=-15
(57)x^2+19x-20=0 答案：x1=-20 x2=1
(58)x^2-7x+6=0 答案：x1=6 x2=1
(59)x^2+4x-221=0 答案：x1=13 x2=-17
(60)x^2+6x-91=0 答案：x1=-13 x2=7
(61)x^2+8x+12=0 答案：x1=-2 x2=-6
(62)x^2+7x-120=0 答案：x1=-15 x2=8
(63)x^2-18x+17=0 答案：x1=17 x2=1
(64)x^2+7x-170=0 答案：x1=-17 x2=10
(65)x^2+6x+8=0 答案：x1=-4 x2=-2
(66)x^2+13x+12=0 答案：x1=-1 x2=-12
(67)x^2+24x+119=0 答案：x1=-7 x2=-17
(68)x^2+11x-42=0 答案：x1=3 x2=-14
(69)x^20x-289=0 答案：x1=17 x2=-17
(70)x^2+13x+30=0 答案：x1=-3 x2=-10
(71)x^2-24x+140=0 答案：x1=14 x2=10
(72)x^2+4x-60=0 答案：x1=-10 x2=6
(73)x^2+27x+170=0 答案：x1=-10 x2=-17
(74)x^2+27x+152=0 答案：x1=-19 x2=-8
(75)x^2-2x-99=0 答案：x1=11 x2=-9
(76)x^2+12x+11=0 答案：x1=-11 x2=-1
(77)x^2+17x+70=0 答案：x1=-10 x2=-7
(78)x^2+20x+19=0 答案：x1=-19 x2=-1
(79)x^2-2x-168=0 答案：x1=-12 x2=14
(80)x^2-13x+30=0 答案：x1=3 x2=10
(81)x^2-10x-119=0 答案：x1=17 x2=-7
(82)x^2+16x-17=0 答案：x1=1 x2=-17
(83)x^2-1x-20=0 答案：x1=5 x2=-4
(84)x^2-2x-288=0 答案：x1=18 x2=-16
(85)x^2-20x+64=0 答案：x1=16 x2=4
(86)x^2+22x+105=0 答案：x1=-7 x2=-15
(87)x^2+13x+12=0 答案：x1=-1 x2=-12
(88)x^2-4x-285=0 答案：x1=19 x2=-15
(89)x^2+26x+133=0 答案：x1=-19 x2=-7
(90)x^2-17x+16=0 答案：x1=1 x2=16
(91)x^2+3x-4=0 答案：x1=1 x2=-4
(92)x^2-14x+48=0 答案：x1=6 x2=8
(93)x^2-12x-133=0 答案：x1=19 x2=-7
(94)x^2+5x+4=0 答案：x1=-1 x2=-4
(95)x^2+6x-91=0 答案：x1=7 x2=-13
(96)x^2+3x-4=0 答案：x1=-4 x2=1
(97)x^2-13x+12=0 答案：x1=12 x2=1
(98)x^2+7x-44=0 答案：x1=-11 x2=4
(99)x^2-6x-7=0 答案：x1=-1 x2=7
(100)x^2-9x-90=0 答案：x1=15 x2=-6
(101)x^2+17x+72=0 答案：x1=-8 x2=-9
(102)x^2+13x-14=0 答案：x1=-14 x2=1
(103)x^2+9x-36=0 答案：x1=-12 x2=3
(104)x^2-9x-90=0 答案：x1=-6 x2=15
(105)x^2+14x+13=0 答案：x1=-1 x2=-13
(106)x^2-16x+63=0 答案：x1=7 x2=9
(107)x^2-15x+44=0 答案：x1=4 x2=11
(108)x^2+2x-168=0 答案：x1=-14 x2=12
(109)x^2-6x-216=0 答案：x1=-12 x2=18
(110)x^2-6x-55=0 答案：x1=11 x2=-5
(111)x^2+18x+32=0 答案：x1=-2 x2=-16 x²-2x-3=0 3,-1
x²-3x-4=0 4,-1
x²-2x+1=0 1,1
x²-4x+3=0 1,3
x²-3x+2=0 1,2
x²-5x+6=0 2,3
x²-5x-6=0 6,-1
x²+5x-6=0 -6,1
x²+5x+6=0 2,3
x²-2x-8=0 4,-2
x²+2x-8=0 -4,2
x²-7x+6=0 1,6
x²-6x-7=0 7,-1
x²-3x-10=0 5,-2
x²-8x-9=0 -1,9
x²-5x-14=0 7,-2
x²-12x+36=0 6,6
x²-9x+20=0 4,5
x²+9x+20=0 -4,-5
x²-20x-44=0 22,-2
(1)x^2-9x 8=0 答案:x1=8 x2=1
(2)x^2 6x-27=0 答案:x1=3 x2=-9
(3)x^2-2x-80=0 答案:x1=-8 x2=10
(4)x^2 10x-200=0 答案:x1=-20 x2=10
(5)x^2-20x 96=0 答案:x1=12 x2=8
(6)x^2 23x 76=0 答案:x1=-19 x2=-4
(7)x^2-25x 154=0 答案:x1=14 x2=11
(8)x^2-12x-108=0 答案:x1=-6 x2=18
(9)x^2 4x-252=0 答案:x1=14 x2=-18
(10)x^2-11x-102=0 答案:x1=17 x2=-6
(11)x^2 15x-54=0 答案:x1=-18 x2=3
(12)x^2 11x 18=0 答案:x1=-2 x2=-9
(13)x^2-9x 20=0 答案:x1=4 x2=5
(14)x^2 19x 90=0 答案:x1=-10 x2=-9
(15)x^2-25x 156=0 答案:x1=13 x2=12
(16)x^2-22x 57=0 答案:x1=3 x2=19
(17)x^2-5x-176=0 答案:x1=16 x2=-11
(18)x^2-26x 133=0 答案:x1=7 x2=19
(19)x^2 10x-11=0 答案:x1=-11 x2=1
(20)x^2-3x-304=0 答案:x1=-16 x2=19
(21)x^2 13x-140=0 答案:x1=7 x2=-20
(22)x^2 13x-48=0 答案:x1=3 x2=-16
(23)x^2 5x-176=0 答案:x1=-16 x2=11
(24)x^2 28x 171=0 答案:x1=-9 x2=-19
(25)x^2 14x 45=0 答案:x1=-9 x2=-5
(26)x^2-9x-136=0 答案:x1=-8 x2=17
(27)x^2-15x-76=0 答案:x1=19 x2=-4
(28)x^2 23x 126=0 答案:x1=-9 x2=-14
(29)x^2 9x-70=0 答案:x1=-14 x2=5
(30)x^2-1x-56=0 答案:x1=8 x2=-7
(31)x^2 7x-60=0 答案:x1=5 x2=-12
(32)x^2 10x-39=0 答案:x1=-13 x2=3
(33)x^2 19x 34=0 答案:x1=-17 x2=-2
(34)x^2-6x-160=0 答案:x1=16 x2=-10
(35)x^2-6x-55=0 答案:x1=11 x2=-5
(36)x^2-7x-144=0 答案:x1=-9 x2=16
(37)x^2 20x 51=0 答案:x1=-3 x2=-17
(38)x^2-9x 14=0 答案:x1=2 x2=7
(39)x^2-29x 208=0 答案:x1=16 x2=13
(40)x^2 19x-20=0 答案:x1=-20 x2=1
(41)x^2-13x-48=0 答案:x1=16 x2=-3
(42)x^2 10x 24=0 答案:x1=-6 x2=-4
(43)x^2 28x 180=0 答案:x1=-10 x2=-18
(44)x^2-8x-209=0 答案:x1=-11 x2=19
(45)x^2 23x 90=0 答案:x1=-18 x2=-5
(46)x^2 7x 6=0 答案:x1=-6 x2=-1
(47)x^2 16x 28=0 答案:x1=-14 x2=-2
(48)x^2 5x-50=0 答案:x1=-10 x2=5
(49)x^2 13x-14=0 答案:x1=1 x2=-14
(50)x^2-23x 102=0 答案:x1=17 x2=6
(51)x^2 5x-176=0 答案:x1=-16 x2=11
(52)x^2-8x-20=0 答案:x1=-2 x2=10
(53)x^2-16x 39=0 答案:x1=3 x2=13
(54)x^2 32x 240=0 答案:x1=-20 x2=-12
(55)x^2 34x 288=0 答案:x1=-18 x2=-16
(56)x^2 22x 105=0 答案:x1=-7 x2=-15
(57)x^2 19x-20=0 答案:x1=-20 x2=1
(58)x^2-7x 6=0 答案:x1=6 x2=1
(59)x^2 4x-221=0 答案:x1=13 x2=-17
(60)x^2 6x-91=0 答案:x1=-13 x2=7
(61)x^2 8x 12=0 答案:x1=-2 x2=-6
(62)x^2 7x-120=0 答案:x1=-15 x2=8
(63)x^2-18x 17=0 答案:x1=17 x2=1
(64)x^2 7x-170=0 答案:x1=-17 x2=10
(65)x^2 6x 8=0 答案:x1=-4 x2=-2
(66)x^2 13x 12=0 答案:x1=-1 x2=-12
(67)x^2 24x 119=0 答案:x1=-7 x2=-17
(68)x^2 11x-42=0 答案:x1=3 x2=-14
(69)x^20x-289=0 答案:x1=17 x2=-17
(70)x^2 13x 30=0 答案:x1=-3 x2=-10
(71)x^2-24x 140=0 答案:x1=14 x2=10
(72)x^2 4x-60=0 答案:x1=-10 x2=6
(73)x^2 27x 170=0 答案:x1=-10 x2=-17
(74)x^2 27x 152=0 答案:x1=-19 x2=-8
(75)x^2-2x-99=0 答案:x1=11 x2=-9
(76)x^2 12x 11=0 答案:x1=-11 x2=-1
(77)x^2 17x 70=0 答案:x1=-10 x2=-7
(78)x^2 20x 19=0 答案:x1=-19 x2=-1
(79)x^2-2x-168=0 答案:x1=-12 x2=14
(80)x^2-13x 30=0 答案:x1=3 x2=10
(81)x^2-10x-119=0 答案:x1=17 x2=-7
(82)x^2 16x-17=0 答案:x1=1 x2=-17
(83)x^2-1x-20=0 答案:x1=5 x2=-4
(84)x^2-2x-288=0 答案:x1=18 x2=-16
(85)x^2-20x 64=0 答案:x1=16 x2=4
(86)x^2 22x 105=0 答案:x1=-7 x2=-15
(87)x^2 13x 12=0 答案:x1=-1 x2=-12
(88)x^2-4x-285=0 答案:x1=19 x2=-15
(89)x^2 26x 133=0 答案:x1=-19 x2=-7
(90)x^2-17x 16=0 答案:x1=1 x2=16
(91)x^2 3x-4=0 答案:x1=1 x2=-4
(92)x^2-14x 48=0 答案:x1=6 x2=8
(93)x^2-12x-133=0 答案:x1=19 x2=-7
(94)x^2 5x 4=0 答案:x1=-1 x2=-4
(95)x^2 6x-91=0 答案:x1=7 x2=-13
(96)x^2 3x-4=0 答案:x1=-4 x2=1
(97)x^2-13x 12=0 答案:x1=12 x2=1
(98)x^2 7x-44=0 答案:x1=-11 x2=4
(99)x^2-6x-7=0 答案:x1=-1 x2=7
(100)x^2-9x-90=0 答案:x1=15 x2=-6
(101)x^2 17x 72=0 答案:x1=-8 x2=-9
(102)x^2 13x-14=0 答案:x1=-14 x2=1
(103)x^2 9x-36=0 答案:x1=-12 x2=3
(104)x^2-9x-90=0 答案:x1=-6 x2=15
(105)x^2 14x 13=0 答案:x1=-1 x2=-13
(106)x^2-16x 63=0 答案:x1=7 x2=9
(107)x^2-15x 44=0 答案:x1=4 x2=11
(108)x^2 2x-168=0 答案:x1=-14 x2=12
(109)x^2-6x-216=0 答案:x1=-12 x2=18
(110)x^2-6x-55=0 答案:x1=11 x2=-5 过程和答案 O(∩_∩)O谢谢
1.(x-5)^2=2(x-5)
(x-5)^2-2(x-5)=0
(x-5)(x-5-2)=0
(x-5)(x-7)=0
x=5,x=7
2.x^2-(√2)*x-1/4=0
x^2-√2x+1/2=1/4+1/2=3/4
(x-√2/2)^2=(±√3/2)^2
x-√2/2=±√3/2
x=(√2+√3)/2,x=(√2-√3)/2
3.x^2+(22√5)*x+10=0
x^2+22√5x+(11√5)^2=-10+(11√5)^2=595
(x+11√5)^2=(±√595)^2
x+11√5=±√595
x=-11√5+√595,x=-11√5-√595
4.已知a,b是方程x^2+x-1=0的两根,求a^2+2a+1/b的值
a是方程的根
所以a^2+a-1=0
a^2+a=1
a^2+2a=a^2+a+a=a+1
所以a^2+2a+1/b=a+1+1/b=(ab+b+1)/b
由韦达定理，ab=-1
所以a^2+2a+1/b=(ab+b+1)/b=(-1+b+1)/b=b/b=1 你可以到这里挑选啊！
http://wenku.baidu.com/search?word=%D2%BB%D4%AA%B6%FE%B4%CE%B7%BD%B3%CC&lm=1&od=0
6X²-7X+1=0
解：6X²-7X=-1
X²-﹙7／6﹚X+﹙7／12﹚²=-1／6﹢﹙7／12﹚²
﹙ X-7／12﹚²=25／144
∴X-7／12=±5／12
∴X1=1，X2=1／6
5X²-18=9X
解：5X²-9X=18
X²-1.8X=3.6
﹙ X-0.9﹚²=4.41
∴X-.9=±2.1
∴X1=3，X2=-1.2
4X²-3X=52
解 ：X²-﹙3／4﹚X=13
﹙ X-3／8﹚²=13
∴X-3／8=±29／8
∴X1=4，X2 =-13／4
5X²=4-2X
解：5X²+2X=4
X²+0.2X=0.8
﹙X+0.1﹚² =0.81
X+0.1=±0.9
X1=-1，X2=0.8 就这么几道,最好去百度搜索，那多 1)x^2-9x+8=0 答案：x1=8 x2=1
(2)x^2+6x-27=0 答案：x1=3 x2=-9
(3)x^2-2x-80=0 答案：x1=-8 x2=10
(4)x^2+10x-200=0 答案：x1=-20 x2=10
(5)x^2-20x+96=0 答案：x1=12 x2=8
(6)x^2+23x+76=0 答案：x1=-19 x2=-4
(7)x^2-25x+154=0 答案：x1=14 x2=11
(8)x^2-12x-108=0 答案：x1=-6 x2=18
(9)x^2+4x-252=0 答案：x1=14 x2=-18
(10)x^2-11x-102=0 答案：x1=17 x2=-6
(11)x^2+15x-54=0 答案：x1=-18 x2=3
(12)x^2+11x+18=0 答案：x1=-2 x2=-9
(13)x^2-9x+20=0 答案：x1=4 x2=5
(14)x^2+19x+90=0 答案：x1=-10 x2=-9
(15)x^2-25x+156=0 答案：x1=13 x2=12
(16)x^2-22x+57=0 答案：x1=3 x2=19
(17)x^2-5x-176=0 答案：x1=16 x2=-11
(18)x^2-26x+133=0 答案：x1=7 x2=19
(19)x^2+10x-11=0 答案：x1=-11 x2=1
(20)x^2-3x-304=0 答案：x1=-16 x2=19
(21)x^2+13x-140=0 答案：x1=7 x2=-20
(22)x^2+13x-48=0 答案：x1=3 x2=-16
(23)x^2+5x-176=0 答案：x1=-16 x2=11
(24)x^2+28x+171=0 答案：x1=-9 x2=-19
(25)x^2+14x+45=0 答案：x1=-9 x2=-5
(26)x^2-9x-136=0 答案：x1=-8 x2=17
(27)x^2-15x-76=0 答案：x1=19 x2=-4
(28)x^2+23x+126=0 答案：x1=-9 x2=-14
(29)x^2+9x-70=0 答案：x1=-14 x2=5
(30)x^2-1x-56=0 答案：x1=8 x2=-7
(31)x^2+7x-60=0 答案：x1=5 x2=-12
(32)x^2+10x-39=0 答案：x1=-13 x2=3
(33)x^2+19x+34=0 答案：x1=-17 x2=-2
(34)x^2-6x-160=0 答案：x1=16 x2=-10
(35)x^2-6x-55=0 答案：x1=11 x2=-5
(36)x^2-7x-144=0 答案：x1=-9 x2=16
(37)x^2+20x+51=0 答案：x1=-3 x2=-17
(38)x^2-9x+14=0 答案：x1=2 x2=7
(39)x^2-29x+208=0 答案：x1=16 x2=13
(40)x^2+19x-20=0 答案：x1=-20 x2=1
(41)x^2-13x-48=0 答案：x1=16 x2=-3
(42)x^2+10x+24=0 答案：x1=-6 x2=-4
(43)x^2+28x+180=0 答案：x1=-10 x2=-18
(44)x^2-8x-209=0 答案：x1=-11 x2=19
(45)x^2+23x+90=0 答案：x1=-18 x2=-5
(46)x^2+7x+6=0 答案：x1=-6 x2=-1
(47)x^2+16x+28=0 答案：x1=-14 x2=-2
(48)x^2+5x-50=0 答案：x1=-10 x2=5
(49)x^2+13x-14=0 答案：x1=1 x2=-14
(50)x^2-23x+102=0 答案：x1=17 x2=6
(51)x^2+5x-176=0 答案：x1=-16 x2=11
(52)x^2-8x-20=0 答案：x1=-2 x2=10
(53)x^2-16x+39=0 答案：x1=3 x2=13
(54)x^2+32x+240=0 答案：x1=-20 x2=-12
(55)x^2+34x+288=0 答案：x1=-18 x2=-16
(56)x^2+22x+105=0 答案：x1=-7 x2=-15
(57)x^2+19x-20=0 答案：x1=-20 x2=1
(58)x^2-7x+6=0 答案：x1=6 x2=1
(59)x^2+4x-221=0 答案：x1=13 x2=-17
(60)x^2+6x-91=0 答案：x1=-13 x2=7
(61)x^2+8x+12=0 答案：x1=-2 x2=-6
(62)x^2+7x-120=0 答案：x1=-15 x2=8
(63)x^2-18x+17=0 答案：x1=17 x2=1
(64)x^2+7x-170=0 答案：x1=-17 x2=10
(65)x^2+6x+8=0 答案：x1=-4 x2=-2
(66)x^2+13x+12=0 答案：x1=-1 x2=-12
(67)x^2+24x+119=0 答案：x1=-7 x2=-17
(68)x^2+11x-42=0 答案：x1=3 x2=-14
(69)x^20x-289=0 答案：x1=17 x2=-17
(70)x^2+13x+30=0 答案：x1=-3 x2=-10
(71)x^2-24x+140=0 答案：x1=14 x2=10
(72)x^2+4x-60=0 答案：x1=-10 x2=6
(73)x^2+27x+170=0 答案：x1=-10 x2=-17
(74)x^2+27x+152=0 答案：x1=-19 x2=-8
(75)x^2-2x-99=0 答案：x1=11 x2=-9
(76)x^2+12x+11=0 答案：x1=-11 x2=-1
(77)x^2+17x+70=0 答案：x1=-10 x2=-7
(78)x^2+20x+19=0 答案：x1=-19 x2=-1
(79)x^2-2x-168=0 答案：x1=-12 x2=14
(80)x^2-13x+30=0 答案：x1=3 x2=10
(81)x^2-10x-119=0 答案：x1=17 x2=-7
(82)x^2+16x-17=0 答案：x1=1 x2=-17
(83)x^2-1x-20=0 答案：x1=5 x2=-4
(84)x^2-2x-288=0 答案：x1=18 x2=-16
(85)x^2-20x+64=0 答案：x1=16 x2=4
(86)x^2+22x+105=0 答案：x1=-7 x2=-15
(87)x^2+13x+12=0 答案：x1=-1 x2=-12
(88)x^2-4x-285=0 答案：x1=19 x2=-15
(89)x^2+26x+133=0 答案：x1=-19 x2=-7
(90)x^2-17x+16=0 答案：x1=1 x2=16
(91)x^2+3x-4=0 答案：x1=1 x2=-4
(92)x^2-14x+48=0 答案：x1=6 x2=8
(93)x^2-12x-133=0 答案：x1=19 x2=-7
(94)x^2+5x+4=0 答案：x1=-1 x2=-4
(95)x^2+6x-91=0 答案：x1=7 x2=-13
(96)x^2+3x-4=0 答案：x1=-4 x2=1
(97)x^2-13x+12=0 答案：x1=12 x2=1
(98)x^2+7x-44=0 答案：x1=-11 x2=4
(99)x^2-6x-7=0 答案：x1=-1 x2=7
(100)x^2-9x-90=0 答案：x1=15 x2=-6
(101)x^2+17x+72=0 答案：x1=-8 x2=-9
(102)x^2+13x-14=0 答案：x1=-14 x2=1
(103)x^2+9x-36=0 答案：x1=-12 x2=3
(104)x^2-9x-90=0 答案：x1=-6 x2=15
(105)x^2+14x+13=0 答案：x1=-1 x2=-13
(106)x^2-16x+63=0 答案：x1=7 x2=9
(107)x^2-15x+44=0 答案：x1=4 x2=11
(108)x^2+2x-168=0 答案：x1=-14 x2=12
(109)x^2-6x-216=0 答案：x1=-12 x2=18
(110)x^2-6x-55=0 答案：x1=11 x2=-5
(111)x^2+18x+32=0 答案：x1=-2 x2=-16
15道九年级一元二次方程计算题
1、解方程：x2—2x—1＝0．
2、解方程：
3、解方程：x2＋x－ ＋1＝0．
4、解方程：
5、 用配方法解方程：
6、解方程：3 ( x - 5 )2 = 2 ( 5- x )
7、解方程： ．
8、
9、解方程：(x -1)2 + 2x (x - 1) = 0
10、解方程： .
11、用配方法解方程： 。
12、解方程： ．
13、解方程：x2－6x＋1＝0．
14、用配方法解一元二次方程：
15、解方程： ．
参考答案
一、计算题
1、解：a=1,b=-2,c=-1
B2-4ac=(-2)2-4*1*(-1)=8
X=
方程的解为x=1+ x=1-
2、原方程化为
∴ ，
3、解：设x2＋x＝y，则原方程变为y－ ＋1＝0．
去分母，整理得y2＋y－6＝0，
解这个方程，得y1＝2，y2＝－3．
当y＝2 时，x2＋x＝2，整理得x2＋x－2＝0，
解这个方程，得x1＝1，x2＝－2．
当y＝－3 时，x2＋x＝－3，整理得x2＋x＋3＝0，
∵△＝12－4×1×3＝－11＜0，所以方程没有实数根．
经检验知原方程的根是x1＝1，x2＝－2．
4、解：移项，得 配方，得
∴ ∴
（注：此题还可用公式法，分解因式法求解，请参照给分）
5、）解：移项，得x2 +5x=－2，
配方，得
整理，得（ ）2=
直接开平方，得 =
∴x1= ，x2=
6、解：
7、解：
∴ 或
∴ ，
8、
9、解法一：
∴ ，
解法二：
∵ a = 3，b = 4，c = 1
∴ ，
10、解： - -两边平方化简，
两边平方化简 . --
解之得 ---
检验：将 .
所以原方程的解为 -
11、解：两边都除以2，得 。
移项，得 。
配方，得 ，
或 。
， 。
12、解：方程两边同乘以 ，得
整理得
经检验 ， 都是原方程的根．
13、解法1：x2－6x＋1＝0
∵ b2－4ac＝(－6)2－4＝32
∴ x＝
＝3±2 .
即x1＝3＋2 ，x2＝3－2 .
解法2：x2－6x＋1＝0
(x－3)2－8＝0
(x－3)2 ＝8
x－3＝±2
即x1＝3＋2 ，x2＝3－2 .
14、 解：移项，得
二次项系数化为1，得
配方
由此可得
15、解法一：
解法二：
（1）(3x+1)^2=7
解：(3x+1)^2=7 ∴(3x+1)^2=7 ∴3x+1=±√7(注意不要丢解) ∴x= (±√7-1)/3
（2）9x^2-24x+16=11
解： 9x^2-24x+16=11 ∴(3x-4)^2=11 ∴3x-4=±√11 ∴x= (±√11+4)/3 ∴原方程的解为x1=(√11+4)/3 x2=(-√11+4)/3
(3) (x+3)(x-6)=-8
解：(x+3)(x-6)=-8 化简整理得 x^2-3x-10=0 (方程左边为二次三项式，右边为零) (x-5)(x+2)=0 (方程左边分解因式) ∴x-5=0或x+2=0 (转化成两个一元一次方程) ∴x1=5,x2=-2是原方程的解。
(4) 2x^2+3x=0
解：2x^2+3x=0 x(2x+3)=0 (用提公因式法将方程左边分解因式) ∴x=0或2x+3=0 (转化成两个一元一次方程) ∴x1=0，x2=-3/2是原方程的解。 注意：有些同学做这种题目时容易丢掉x=0这个解，应记住一元二次方程有两个解。
(5) 6x^2+5x-50=0 (选学）
解：6x2+5x-50=0 (2x-5)(3x+10)=0 (十字相乘分解因式时要特别注意符号不要出错) ∴2x-5=0或3x+10=0 ∴x1=5/2, x2=-10/3 是原方程的解。
(6)x^2-4x+4=0 （选学）
解：x^2-4x+4 =0 （∵4 可分解为2 ·2 ，∴此题可用因式分解法） (x-2)(x-2 )=0 ∴x1=2 ,x2=2是原方程的解。
(7)（x-2）^2=4（2x+3）^2
解.(x-2)^2-4(2x+3)^2=0. [x-2+2(2x+3)][(x-2-2(2x+3)=0.
(5x+4)(-5x-8)=0.
x1=-4/5, x2=-8/5
（8）y^2+2√2y-4=0
解(y+√2)^2-2-4=0.
(y+ √2)^2=6.
y+√2=√6.
y=-√2±√6.
y1=-√2+√6；
y2=-√2-√6.
（9）（x+1）^2-3（x+1)+2=0
解(x+1-1)(x+1-2)=0.
x(x-1)=0.
x1=0,
x2=1.
（10）x^2+2ax-3a^2=0（a为常数）
解 (x+3a)(x-a)=0.
x1=-3a,
x2=a.
(11)2x^2＋7x＝4．
解：方程可变形为2x^2＋7x－4＝0．
∵a＝2，b＝7，c＝－4，b2－4ac＝72－4×2×(－4)＝81＞0，
∴x＝ ．∴x1＝ ，x2＝－4．
(12)x^2－1＝2 x
解：方程可变形为x^2－2 x－1＝0．
∵a＝1，b＝－2 ，c＝－1，b2－4ac＝(－2 )2－4×1×(－1)＝16＞0．
∴x＝ ．∴x1＝ ＋2，x2＝ －2
（13） x^2 + 6x+5=0
解：原方程可化为(x+5)(x+1)=0
x1=-5 x2=-1
(14) x ^2－4x+ 3=0
解：原方程可化为(x-3)(x-1)=0
x1=3 x2=1
(15)7x^2 －4x－3 =0
解原方程可化为 (7x+3)(x-1)=0
x1=-3/7 x2=1
(16)x ^2－6x+9 =0
解原方程可化为
(x-3)^2=0
x1=x2=3
(17)x²+8x+16=9
解：(x+4)²=9
x+4=3或x+4=-3
x1=-1,x2=-7
(18)(x²-5)²=16
解：x²-5=4或x²-5=-4
x²=9或x²=1
x1=3,x2=-3,x3=1,x4=-1
(19)x(x+2)=x(3-x)+1
解x²+2x=3x-x²+1
2x²-x-1=0
(2x+1)(x-1)=0
x1=-1/2 x=1
(20) 6x^2+x-2=0
解原方程可化为(3x+2)(2x-1)=0
(x+2/3)(x-1/2)=0
x1=-2/3 x2=1/2
这是20道有过程的，还有一些没有过程，只有答案的。
1)x^2-9x+8=0 答案：x1=8 x2=1
(2)x^2+6x-27=0 答案：x1=3 x2=-9
(3)x^2-2x-80=0 答案：x1=-8 x2=10
(4)x^2+10x-200=0 答案：x1=-20 x2=10
(5)x^2-20x+96=0 答案：x1=12 x2=8
(6)x^2+23x+76=0 答案：x1=-19 x2=-4
(7)x^2-25x+154=0 答案：x1=14 x2=11
(8)x^2-12x-108=0 答案：x1=-6 x2=18
(9)x^2+4x-252=0 答案：x1=14 x2=-18
(10)x^2-11x-102=0 答案：x1=17 x2=-6
(11)x^2+15x-54=0 答案：x1=-18 x2=3
(12)x^2+11x+18=0 答案：x1=-2 x2=-9
(13)x^2-9x+20=0 答案：x1=4 x2=5
(14)x^2+19x+90=0 答案：x1=-10 x2=-9
(15)x^2-25x+156=0 答案：x1=13 x2=12
(16)x^2-22x+57=0 答案：x1=3 x2=19
(17)x^2-5x-176=0 答案：x1=16 x2=-11
(18)x^2-26x+133=0 答案：x1=7 x2=19
(19)x^2+10x-11=0 答案：x1=-11 x2=1
(20)x^2-3x-304=0 答案：x1=-16 x2=19
(21)x^2+13x-140=0 答案：x1=7 x2=-20
(22)x^2+13x-48=0 答案：x1=3 x2=-16
(23)x^2+5x-176=0 答案：x1=-16 x2=11
(24)x^2+28x+171=0 答案：x1=-9 x2=-19
(25)x^2+14x+45=0 答案：x1=-9 x2=-5
(26)x^2-9x-136=0 答案：x1=-8 x2=17
(27)x^2-15x-76=0 答案：x1=19 x2=-4
(28)x^2+23x+126=0 答案：x1=-9 x2=-14
(29)x^2+9x-70=0 答案：x1=-14 x2=5
(30)x^2-1x-56=0 答案：x1=8 x2=-7
(31)x^2+7x-60=0 答案：x1=5 x2=-12
(32)x^2+10x-39=0 答案：x1=-13 x2=3
(33)x^2+19x+34=0 答案：x1=-17 x2=-2
(34)x^2-6x-160=0 答案：x1=16 x2=-10
(35)x^2-6x-55=0 答案：x1=11 x2=-5
(36)x^2-7x-144=0 答案：x1=-9 x2=16
(37)x^2+20x+51=0 答案：x1=-3 x2=-17
(38)x^2-9x+14=0 答案：x1=2 x2=7
(39)x^2-29x+208=0 答案：x1=16 x2=13
(40)x^2+19x-20=0 答案：x1=-20 x2=1
(41)x^2-13x-48=0 答案：x1=16 x2=-3
(42)x^2+10x+24=0 答案：x1=-6 x2=-4
(43)x^2+28x+180=0 答案：x1=-10 x2=-18
(44)x^2-8x-209=0 答案：x1=-11 x2=19
(45)x^2+23x+90=0 答案：x1=-18 x2=-5
(46)x^2+7x+6=0 答案：x1=-6 x2=-1
(47)x^2+16x+28=0 答案：x1=-14 x2=-2
(48)x^2+5x-50=0 答案：x1=-10 x2=5
(49)x^2+13x-14=0 答案：x1=1 x2=-14
(50)x^2-23x+102=0 答案：x1=17 x2=6
(51)x^2+5x-176=0 答案：x1=-16 x2=11
(52)x^2-8x-20=0 答案：x1=-2 x2=10
(53)x^2-16x+39=0 答案：x1=3 x2=13
(54)x^2+32x+240=0 答案：x1=-20 x2=-12
(55)x^2+34x+288=0 答案：x1=-18 x2=-16
(56)x^2+22x+105=0 答案：x1=-7 x2=-15
(57)x^2+19x-20=0 答案：x1=-20 x2=1
(58)x^2-7x+6=0 答案：x1=6 x2=1
(59)x^2+4x-221=0 答案：x1=13 x2=-17
(60)x^2+6x-91=0 答案：x1=-13 x2=7
(61)x^2+8x+12=0 答案：x1=-2 x2=-6
(62)x^2+7x-120=0 答案：x1=-15 x2=8
(63)x^2-18x+17=0 答案：x1=17 x2=1
(64)x^2+7x-170=0 答案：x1=-17 x2=10
(65)x^2+6x+8=0 答案：x1=-4 x2=-2
(66)x^2+13x+12=0 答案：x1=-1 x2=-12
(67)x^2+24x+119=0 答案：x1=-7 x2=-17
(68)x^2+11x-42=0 答案：x1=3 x2=-14
(69)x^20x-289=0 答案：x1=17 x2=-17
(70)x^2+13x+30=0 答案：x1=-3 x2=-10
(71)x^2-24x+140=0 答案：x1=14 x2=10
(72)x^2+4x-60=0 答案：x1=-10 x2=6
(73)x^2+27x+170=0 答案：x1=-10 x2=-17
(74)x^2+27x+152=0 答案：x1=-19 x2=-8
(75)x^2-2x-99=0 答案：x1=11 x2=-9
(76)x^2+12x+11=0 答案：x1=-11 x2=-1
(77)x^2+17x+70=0 答案：x1=-10 x2=-7
(78)x^2+20x+19=0 答案：x1=-19 x2=-1
(79)x^2-2x-168=0 答案：x1=-12 x2=14
(80)x^2-13x+30=0 答案：x1=3 x2=10
(81)x^2-10x-119=0 答案：x1=17 x2=-7
(82)x^2+16x-17=0 答案：x1=1 x2=-17
(83)x^2-1x-20=0 答案：x1=5 x2=-4
(84)x^2-2x-288=0 答案：x1=18 x2=-16
(85)x^2-20x+64=0 答案：x1=16 x2=4
(86)x^2+22x+105=0 答案：x1=-7 x2=-15
(87)x^2+13x+12=0 答案：x1=-1 x2=-12
(88)x^2-4x-285=0 答案：x1=19 x2=-15
(89)x^2+26x+133=0 答案：x1=-19 x2=-7
(90)x^2-17x+16=0 答案：x1=1 x2=16
(91)x^2+3x-4=0 答案：x1=1 x2=-4
(92)x^2-14x+48=0 答案：x1=6 x2=8
(93)x^2-12x-133=0 答案：x1=19 x2=-7
(94)x^2+5x+4=0 答案：x1=-1 x2=-4
(95)x^2+6x-91=0 答案：x1=7 x2=-13
(96)x^2+3x-4=0 答案：x1=-4 x2=1
(97)x^2-13x+12=0 答案：x1=12 x2=1
(98)x^2+7x-44=0 答案：x1=-11 x2=4
(99)x^2-6x-7=0 答案：x1=-1 x2=7
(100)x^2-9x-90=0 答案：x1=15 x2=-6
(101)x^2+17x+72=0 答案：x1=-8 x2=-9
(102)x^2+13x-14=0 答案：x1=-14 x2=1
(103)x^2+9x-36=0 答案：x1=-12 x2=3
(104)x^2-9x-90=0 答案：x1=-6 x2=15
(105)x^2+14x+13=0 答案：x1=-1 x2=-13
(106)x^2-16x+63=0 答案：x1=7 x2=9
(107)x^2-15x+44=0 答案：x1=4 x2=11
(108)x^2+2x-168=0 答案：x1=-14 x2=12
(109)x^2-6x-216=0 答案：x1=-12 x2=18
(110)x^2-6x-55=0 答案：x1=11 x2=-5
(111)x^2+18x+32=0 答案：x1=-2 x2=-16 x²-2x-3=0 3,-1
x²-3x-4=0 4,-1
x²-2x+1=0 1,1
x²-4x+3=0 1,3
x²-3x+2=0 1,2
x²-5x+6=0 2,3
x²-5x-6=0 6,-1
x²+5x-6=0 -6,1
x²+5x+6=0 2,3
x²-2x-8=0 4,-2
x²+2x-8=0 -4,2
x²-7x+6=0 1,6
x²-6x-7=0 7,-1
x²-3x-10=0 5,-2
x²-8x-9=0 -1,9
x²-5x-14=0 7,-2
x²-12x+36=0 6,6
x²-9x+20=0 4,5
x²+9x+20=0 -4,-5
x²-20x-44=0 22,-2
(1)x^2-9x 8=0 答案:x1=8 x2=1
(2)x^2 6x-27=0 答案:x1=3 x2=-9
(3)x^2-2x-80=0 答案:x1=-8 x2=10
(4)x^2 10x-200=0 答案:x1=-20 x2=10
(5)x^2-20x 96=0 答案:x1=12 x2=8
(6)x^2 23x 76=0 答案:x1=-19 x2=-4
(7)x^2-25x 154=0 答案:x1=14 x2=11
(8)x^2-12x-108=0 答案:x1=-6 x2=18
(9)x^2 4x-252=0 答案:x1=14 x2=-18
(10)x^2-11x-102=0 答案:x1=17 x2=-6
(11)x^2 15x-54=0 答案:x1=-18 x2=3
(12)x^2 11x 18=0 答案:x1=-2 x2=-9
(13)x^2-9x 20=0 答案:x1=4 x2=5
(14)x^2 19x 90=0 答案:x1=-10 x2=-9
(15)x^2-25x 156=0 答案:x1=13 x2=12
(16)x^2-22x 57=0 答案:x1=3 x2=19
(17)x^2-5x-176=0 答案:x1=16 x2=-11
(18)x^2-26x 133=0 答案:x1=7 x2=19
(19)x^2 10x-11=0 答案:x1=-11 x2=1
(20)x^2-3x-304=0 答案:x1=-16 x2=19
(21)x^2 13x-140=0 答案:x1=7 x2=-20
(22)x^2 13x-48=0 答案:x1=3 x2=-16
(23)x^2 5x-176=0 答案:x1=-16 x2=11
(24)x^2 28x 171=0 答案:x1=-9 x2=-19
(25)x^2 14x 45=0 答案:x1=-9 x2=-5
(26)x^2-9x-136=0 答案:x1=-8 x2=17
(27)x^2-15x-76=0 答案:x1=19 x2=-4
(28)x^2 23x 126=0 答案:x1=-9 x2=-14
(29)x^2 9x-70=0 答案:x1=-14 x2=5
(30)x^2-1x-56=0 答案:x1=8 x2=-7
(31)x^2 7x-60=0 答案:x1=5 x2=-12
(32)x^2 10x-39=0 答案:x1=-13 x2=3
(33)x^2 19x 34=0 答案:x1=-17 x2=-2
(34)x^2-6x-160=0 答案:x1=16 x2=-10
(35)x^2-6x-55=0 答案:x1=11 x2=-5
(36)x^2-7x-144=0 答案:x1=-9 x2=16
(37)x^2 20x 51=0 答案:x1=-3 x2=-17
(38)x^2-9x 14=0 答案:x1=2 x2=7
(39)x^2-29x 208=0 答案:x1=16 x2=13
(40)x^2 19x-20=0 答案:x1=-20 x2=1
(41)x^2-13x-48=0 答案:x1=16 x2=-3
(42)x^2 10x 24=0 答案:x1=-6 x2=-4
(43)x^2 28x 180=0 答案:x1=-10 x2=-18
(44)x^2-8x-209=0 答案:x1=-11 x2=19
(45)x^2 23x 90=0 答案:x1=-18 x2=-5
(46)x^2 7x 6=0 答案:x1=-6 x2=-1
(47)x^2 16x 28=0 答案:x1=-14 x2=-2
(48)x^2 5x-50=0 答案:x1=-10 x2=5
(49)x^2 13x-14=0 答案:x1=1 x2=-14
(50)x^2-23x 102=0 答案:x1=17 x2=6
(51)x^2 5x-176=0 答案:x1=-16 x2=11
(52)x^2-8x-20=0 答案:x1=-2 x2=10
(53)x^2-16x 39=0 答案:x1=3 x2=13
(54)x^2 32x 240=0 答案:x1=-20 x2=-12
(55)x^2 34x 288=0 答案:x1=-18 x2=-16
(56)x^2 22x 105=0 答案:x1=-7 x2=-15
(57)x^2 19x-20=0 答案:x1=-20 x2=1
(58)x^2-7x 6=0 答案:x1=6 x2=1
(59)x^2 4x-221=0 答案:x1=13 x2=-17
(60)x^2 6x-91=0 答案:x1=-13 x2=7
(61)x^2 8x 12=0 答案:x1=-2 x2=-6
(62)x^2 7x-120=0 答案:x1=-15 x2=8
(63)x^2-18x 17=0 答案:x1=17 x2=1
(64)x^2 7x-170=0 答案:x1=-17 x2=10
(65)x^2 6x 8=0 答案:x1=-4 x2=-2
(66)x^2 13x 12=0 答案:x1=-1 x2=-12
(67)x^2 24x 119=0 答案:x1=-7 x2=-17
(68)x^2 11x-42=0 答案:x1=3 x2=-14
(69)x^20x-289=0 答案:x1=17 x2=-17
(70)x^2 13x 30=0 答案:x1=-3 x2=-10
(71)x^2-24x 140=0 答案:x1=14 x2=10
(72)x^2 4x-60=0 答案:x1=-10 x2=6
(73)x^2 27x 170=0 答案:x1=-10 x2=-17
(74)x^2 27x 152=0 答案:x1=-19 x2=-8
(75)x^2-2x-99=0 答案:x1=11 x2=-9
(76)x^2 12x 11=0 答案:x1=-11 x2=-1
(77)x^2 17x 70=0 答案:x1=-10 x2=-7
(78)x^2 20x 19=0 答案:x1=-19 x2=-1
(79)x^2-2x-168=0 答案:x1=-12 x2=14
(80)x^2-13x 30=0 答案:x1=3 x2=10
(81)x^2-10x-119=0 答案:x1=17 x2=-7
(82)x^2 16x-17=0 答案:x1=1 x2=-17
(83)x^2-1x-20=0 答案:x1=5 x2=-4
(84)x^2-2x-288=0 答案:x1=18 x2=-16
(85)x^2-20x 64=0 答案:x1=16 x2=4
(86)x^2 22x 105=0 答案:x1=-7 x2=-15
(87)x^2 13x 12=0 答案:x1=-1 x2=-12
(88)x^2-4x-285=0 答案:x1=19 x2=-15
(89)x^2 26x 133=0 答案:x1=-19 x2=-7
(90)x^2-17x 16=0 答案:x1=1 x2=16
(91)x^2 3x-4=0 答案:x1=1 x2=-4
(92)x^2-14x 48=0 答案:x1=6 x2=8
(93)x^2-12x-133=0 答案:x1=19 x2=-7
(94)x^2 5x 4=0 答案:x1=-1 x2=-4
(95)x^2 6x-91=0 答案:x1=7 x2=-13
(96)x^2 3x-4=0 答案:x1=-4 x2=1
(97)x^2-13x 12=0 答案:x1=12 x2=1
(98)x^2 7x-44=0 答案:x1=-11 x2=4
(99)x^2-6x-7=0 答案:x1=-1 x2=7
(100)x^2-9x-90=0 答案:x1=15 x2=-6
(101)x^2 17x 72=0 答案:x1=-8 x2=-9
(102)x^2 13x-14=0 答案:x1=-14 x2=1
(103)x^2 9x-36=0 答案:x1=-12 x2=3
(104)x^2-9x-90=0 答案:x1=-6 x2=15
(105)x^2 14x 13=0 答案:x1=-1 x2=-13
(106)x^2-16x 63=0 答案:x1=7 x2=9
(107)x^2-15x 44=0 答案:x1=4 x2=11
(108)x^2 2x-168=0 答案:x1=-14 x2=12
(109)x^2-6x-216=0 答案:x1=-12 x2=18
(110)x^2-6x-55=0 答案:x1=11 x2=-5 过程和答案 O(∩_∩)O谢谢
1.(x-5)^2=2(x-5)
(x-5)^2-2(x-5)=0
(x-5)(x-5-2)=0
(x-5)(x-7)=0
x=5,x=7
2.x^2-(√2)*x-1/4=0
x^2-√2x+1/2=1/4+1/2=3/4
(x-√2/2)^2=(±√3/2)^2
x-√2/2=±√3/2
x=(√2+√3)/2,x=(√2-√3)/2
3.x^2+(22√5)*x+10=0
x^2+22√5x+(11√5)^2=-10+(11√5)^2=595
(x+11√5)^2=(±√595)^2
x+11√5=±√595
x=-11√5+√595,x=-11√5-√595
4.已知a,b是方程x^2+x-1=0的两根,求a^2+2a+1/b的值
a是方程的根
所以a^2+a-1=0
a^2+a=1
a^2+2a=a^2+a+a=a+1
所以a^2+2a+1/b=a+1+1/b=(ab+b+1)/b
由韦达定理，ab=-1
所以a^2+2a+1/b=(ab+b+1)/b=(-1+b+1)/b=b/b=1 你可以到这里挑选啊！
http://wenku.baidu.com/search?word=%D2%BB%D4%AA%B6%FE%B4%CE%B7%BD%B3%CC&lm=1&od=0
6X²-7X+1=0
解：6X²-7X=-1
X²-﹙7／6﹚X+﹙7／12﹚²=-1／6﹢﹙7／12﹚²
﹙ X-7／12﹚²=25／144
∴X-7／12=±5／12
∴X1=1，X2=1／6
5X²-18=9X
解：5X²-9X=18
X²-1.8X=3.6
﹙ X-0.9﹚²=4.41
∴X-.9=±2.1
∴X1=3，X2=-1.2
4X²-3X=52
解 ：X²-﹙3／4﹚X=13
﹙ X-3／8﹚²=13
∴X-3／8=±29／8
∴X1=4，X2 =-13／4
5X²=4-2X
解：5X²+2X=4
X²+0.2X=0.8
﹙X+0.1﹚² =0.81
X+0.1=±0.9
X1=-1，X2=0.8 就这么几道,最好去百度搜索，那多 1)x^2-9x+8=0 答案：x1=8 x2=1
(2)x^2+6x-27=0 答案：x1=3 x2=-9
(3)x^2-2x-80=0 答案：x1=-8 x2=10
(4)x^2+10x-200=0 答案：x1=-20 x2=10
(5)x^2-20x+96=0 答案：x1=12 x2=8
(6)x^2+23x+76=0 答案：x1=-19 x2=-4
(7)x^2-25x+154=0 答案：x1=14 x2=11
(8)x^2-12x-108=0 答案：x1=-6 x2=18
(9)x^2+4x-252=0 答案：x1=14 x2=-18
(10)x^2-11x-102=0 答案：x1=17 x2=-6
(11)x^2+15x-54=0 答案：x1=-18 x2=3
(12)x^2+11x+18=0 答案：x1=-2 x2=-9
(13)x^2-9x+20=0 答案：x1=4 x2=5
(14)x^2+19x+90=0 答案：x1=-10 x2=-9
(15)x^2-25x+156=0 答案：x1=13 x2=12
(16)x^2-22x+57=0 答案：x1=3 x2=19
(17)x^2-5x-176=0 答案：x1=16 x2=-11
(18)x^2-26x+133=0 答案：x1=7 x2=19
(19)x^2+10x-11=0 答案：x1=-11 x2=1
(20)x^2-3x-304=0 答案：x1=-16 x2=19
(21)x^2+13x-140=0 答案：x1=7 x2=-20
(22)x^2+13x-48=0 答案：x1=3 x2=-16
(23)x^2+5x-176=0 答案：x1=-16 x2=11
(24)x^2+28x+171=0 答案：x1=-9 x2=-19
(25)x^2+14x+45=0 答案：x1=-9 x2=-5
(26)x^2-9x-136=0 答案：x1=-8 x2=17
(27)x^2-15x-76=0 答案：x1=19 x2=-4
(28)x^2+23x+126=0 答案：x1=-9 x2=-14
(29)x^2+9x-70=0 答案：x1=-14 x2=5
(30)x^2-1x-56=0 答案：x1=8 x2=-7
(31)x^2+7x-60=0 答案：x1=5 x2=-12
(32)x^2+10x-39=0 答案：x1=-13 x2=3
(33)x^2+19x+34=0 答案：x1=-17 x2=-2
(34)x^2-6x-160=0 答案：x1=16 x2=-10
(35)x^2-6x-55=0 答案：x1=11 x2=-5
(36)x^2-7x-144=0 答案：x1=-9 x2=16
(37)x^2+20x+51=0 答案：x1=-3 x2=-17
(38)x^2-9x+14=0 答案：x1=2 x2=7
(39)x^2-29x+208=0 答案：x1=16 x2=13
(40)x^2+19x-20=0 答案：x1=-20 x2=1
(41)x^2-13x-48=0 答案：x1=16 x2=-3
(42)x^2+10x+24=0 答案：x1=-6 x2=-4
(43)x^2+28x+180=0 答案：x1=-10 x2=-18
(44)x^2-8x-209=0 答案：x1=-11 x2=19
(45)x^2+23x+90=0 答案：x1=-18 x2=-5
(46)x^2+7x+6=0 答案：x1=-6 x2=-1
(47)x^2+16x+28=0 答案：x1=-14 x2=-2
(48)x^2+5x-50=0 答案：x1=-10 x2=5
(49)x^2+13x-14=0 答案：x1=1 x2=-14
(50)x^2-23x+102=0 答案：x1=17 x2=6
(51)x^2+5x-176=0 答案：x1=-16 x2=11
(52)x^2-8x-20=0 答案：x1=-2 x2=10
(53)x^2-16x+39=0 答案：x1=3 x2=13
(54)x^2+32x+240=0 答案：x1=-20 x2=-12
(55)x^2+34x+288=0 答案：x1=-18 x2=-16
(56)x^2+22x+105=0 答案：x1=-7 x2=-15
(57)x^2+19x-20=0 答案：x1=-20 x2=1
(58)x^2-7x+6=0 答案：x1=6 x2=1
(59)x^2+4x-221=0 答案：x1=13 x2=-17
(60)x^2+6x-91=0 答案：x1=-13 x2=7
(61)x^2+8x+12=0 答案：x1=-2 x2=-6
(62)x^2+7x-120=0 答案：x1=-15 x2=8
(63)x^2-18x+17=0 答案：x1=17 x2=1
(64)x^2+7x-170=0 答案：x1=-17 x2=10
(65)x^2+6x+8=0 答案：x1=-4 x2=-2
(66)x^2+13x+12=0 答案：x1=-1 x2=-12
(67)x^2+24x+119=0 答案：x1=-7 x2=-17
(68)x^2+11x-42=0 答案：x1=3 x2=-14
(69)x^20x-289=0 答案：x1=17 x2=-17
(70)x^2+13x+30=0 答案：x1=-3 x2=-10
(71)x^2-24x+140=0 答案：x1=14 x2=10
(72)x^2+4x-60=0 答案：x1=-10 x2=6
(73)x^2+27x+170=0 答案：x1=-10 x2=-17
(74)x^2+27x+152=0 答案：x1=-19 x2=-8
(75)x^2-2x-99=0 答案：x1=11 x2=-9
(76)x^2+12x+11=0 答案：x1=-11 x2=-1
(77)x^2+17x+70=0 答案：x1=-10 x2=-7
(78)x^2+20x+19=0 答案：x1=-19 x2=-1
(79)x^2-2x-168=0 答案：x1=-12 x2=14
(80)x^2-13x+30=0 答案：x1=3 x2=10
(81)x^2-10x-119=0 答案：x1=17 x2=-7
(82)x^2+16x-17=0 答案：x1=1 x2=-17
(83)x^2-1x-20=0 答案：x1=5 x2=-4
(84)x^2-2x-288=0 答案：x1=18 x2=-16
(85)x^2-20x+64=0 答案：x1=16 x2=4
(86)x^2+22x+105=0 答案：x1=-7 x2=-15
(87)x^2+13x+12=0 答案：x1=-1 x2=-12
(88)x^2-4x-285=0 答案：x1=19 x2=-15
(89)x^2+26x+133=0 答案：x1=-19 x2=-7
(90)x^2-17x+16=0 答案：x1=1 x2=16
(91)x^2+3x-4=0 答案：x1=1 x2=-4
(92)x^2-14x+48=0 答案：x1=6 x2=8
(93)x^2-12x-133=0 答案：x1=19 x2=-7
(94)x^2+5x+4=0 答案：x1=-1 x2=-4
(95)x^2+6x-91=0 答案：x1=7 x2=-13
(96)x^2+3x-4=0 答案：x1=-4 x2=1
(97)x^2-13x+12=0 答案：x1=12 x2=1
(98)x^2+7x-44=0 答案：x1=-11 x2=4
(99)x^2-6x-7=0 答案：x1=-1 x2=7
(100)x^2-9x-90=0 答案：x1=15 x2=-6
(101)x^2+17x+72=0 答案：x1=-8 x2=-9
(102)x^2+13x-14=0 答案：x1=-14 x2=1
(103)x^2+9x-36=0 答案：x1=-12 x2=3
(104)x^2-9x-90=0 答案：x1=-6 x2=15
(105)x^2+14x+13=0 答案：x1=-1 x2=-13
(106)x^2-16x+63=0 答案：x1=7 x2=9
(107)x^2-15x+44=0 答案：x1=4 x2=11
(108)x^2+2x-168=0 答案：x1=-14 x2=12
(109)x^2-6x-216=0 答案：x1=-12 x2=18
(110)x^2-6x-55=0 答案：x1=11 x2=-5
(111)x^2+18x+32=0 答案：x1=-2 x2=-16
