一元二次方程练习题-含答案(解法20题-题海111题)

1、经典解法20题(1) (3x+1)A2=7(2) 9xA2-24x+16=11(3) (x+3)(x-6)=-8(4) 2xA2+3x=0(5) 6xA2+5x-50=0 ( 选学)(6)xA2-4x+4=0 (选学)(7) (x-2 ) A2=4 (2x+3 )卜2(8) yA2+2 v2y-4=0(9) (x+1 ) A2-3 (x+1)+2=0(10) xA2+2ax-3aA2=0（a为常数）(11)2xA2 +7x=4.(12)xA2 1=2 x(13) xA2 + 6x+5=0(14) x A2 -4x+ 3=0(15)7xA2-4x-3 =0(16)x A2 -6x+9 =0(17

2、)x2+8x+16=9(18)(x 2-5) 2=16(19)x(x+2)=x(3-x)+1(20)6xA2+x-2=0(22)xA2+13x-48=0海量111题1)xA2-9x+8=0(2)xA2+6x-27=0(3)xA2-2x-80=0(4)xA2+10x-200=0(5)xA2-20x+96=0(6)xA2+23x+76=0(7)xA2-25x+154=0(8)xA2-12x-108=0(9)xA2+4x-252=0(10)xA2-11x-102=0(11)xA2+15x-54=0(12)xA2+11x+18=0(13)xA2-9x+20=0(14)xA2+19x+90=0(15)x

3、A2-25x+156=0(16)xA2-22x+57=0(17)xA2-5x-176=0(18)xA2-26x+133=0(19)xA2+10x-11=0(20)xA2-3x-304=0(23)xA2+5x-176=0(24)xA2+28x+171=0(25)xA2+14x+45=0(26)xA2-9x-136=0(27)xA2-15x-76=0(28)xA2+23x+126=0(29)xA2+9x-70=0(30)xA2-1x-56=0(31)xA2+7x-60=0(32)xA2+10x-39=0(33)xA2+19x+34=0(34)xA2-6x-160=0(35)xA2-6x-55=0(

4、36)xA2-7x-144=0(37)xA2+20x+51=0(38)xA2-9x+14=0(39)xA2-29x+208=0(40)xA2+19x-20=0(41)xA2-13x-48=0(42)xA2+10x+24=0 (43)xA2+28x+180=0(66)xA2+13x+12=0(45)xA2+23x+90=0(46)xA2+7x+6=0(47)xA2+16x+28=0(48)xA2+5x-50=0(49)xA2+13x-14=0(50)xA2-23x+102=0(51)xA2+5x-176=0(52)xA2-8x-20=0(53)xA2-16x+39=0(54)xA2+32x+24

5、0=0(55)xA2+34x+288=0(56)xA2+22x+105=0(57)xA2+19x-20=0(58)xA2-7x+6=0(59)xA2+4x-221=0(60)xA2+6x-91=0(61)xA2+8x+12=0(62)xA2+7x-120=0(63)xA2-18x+17=0(64)xA2+7x-170=0(67)xA2+24x+119=0(68)xA2+11x-42=0(69)xA20x-289=0(70)xA2+13x+30=0(71 )xA2-24x+140=0(72)xA2+4x-60=0(73)xA2+27x+170=0(74)xA2+27x+152=0(75)xA2-

6、2x-99=0(76)xA2+12x+11=0(77)xA2+17x+70=0(78)xA2+20x+19=0(79)xA2-2x-168=0(80)xA2-13x+30=0(81)xA2-10x-119=0(82)xA2+16x-17=0(83)xA2-1x-20=0(84)xA2-2x-288=0(85)xA2-20x+64=0(86)xA2+22x+105=0(87)xA2+13x+12=0(88)xA2-4x-285=0(89)xA2+26x+133=0(90)xA2-17x+16=0(91)xA2+3x-4=0(92)xA2-14x+48=0(93)xA2-12x-133=0(94)

7、xA2+5x+4=0(95)xA2+6x-91=0(96)xA2+3x-4=0(97)xA2-13x+12=0(98)xA2+7x-44=0(99)xA2-6x-7=0(100)xA2-9x-90=0(101)xA2+17x+72=0(102)xA2+13x-14=0(103)xA2+9x-36=0(104)xA2-9x-90=0(105)xA2+14x+13=0(106)xA2-16x+63=0(107)xA2-15x+44=0(108)xA2+2x-168=0(109)xA2-6x-216=0(110)xA2-6x-55=0(111)xA2+18x+32=0答案(1) (3x+1)A2=7

8、解：(3x+1)A2=7；(3x+1)A2=7；3x+1= ±4(注意不要丢解)；x二 ( ±V7-1)/3(2) 9xA2-24x+16=11解：9xA2-24x+16=11.(3x-4)A2=11.3x-4= ±1. x= (土，11+4)/3原方程的解为 x1=( M1+4)/3x2=(- l1+4)/3(3) (x+3)(x-6)=-8解：(x+3)(x-6)=-8化简整理得xA2-3x-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

9、原方程的解。 2xA2+3x=0解：2xA2+3x=0x(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) 6xA2+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)xA2-4x+4=0(选学)解：xA2-4x+4 =0( 44可分解为2 2，此题可用因式

10、分解法)(x-2)(x-2 )=0. x1=2 ,x2=2 是原方程的解。(7) (x-2 ) A2=4 (2x+3 ) A2解.(x-2)A2-4(2x+3)A2=0.x-2+2(2x+3)(x-2-2(2x+3)=0.(5x+4)(-5x-8)=0.x1=-4/5, x2=-8/5(8) yA2+2 V2y-4=0解(y+ V2)A2-2-4=0.(y+ V2)A2=6.y+ v2= v6.y=- v2 ± a6.y1=- v2+ v6 ；y2=- v2- v6.(9) (x+1 ) A2-3 (x+1)+2=0解(x+1-1)(x+1-2)=0.x(x-1)=0.x1=0,x2

11、=1.(10) xA2+2ax-3aA2=0(a 为常数)解(x+3a)(x-a)=0.x1=-3a,x2=a.(11)2xA2 +7x=4.解：(x+4) 2=9. a = 2, b = 7, c= 4, b2 4ac = 72 4 X2 X(4) = 81 >0, x= . -'x1 = , x2 = 4 .(12)xA2 1=2 x解：方程可变形为xA2 -2 x 1=0.a=1, b = 2 , c=1, b24ac = ( 2 )2 4X1 X(1) = 16 >0 . x= . . x1 = +2, x2= -2(13) xA2 + 6x+5=0解：原方程可化为

12、(x+5)(x+1)=0x1=-5x2=-1(14) x A2 -4x+ 3=0解：原方程可化为(x-3)(x-1)=0x1=3x2=1(15)7xA2-4x-3 =0解原方程可化为(7x+3)(x-1)=0x1=-3/7x2=1(16)x A2 -6x+9 =0解原方程可化为(x-3)A2=0x1=x2=3x+4=3 或 x+4=-3x1=-1,x2=-7(18)(x 2-5) 2=16解：x2-5=4 或 x2-5=-4x2=9 或 x2=1x1=3,x2=-3,x3=1,x4=-1(19)x(x+2)=x(3-x)+1解 x2+2x=3x-x 2+12x2-x-1=0(2x+1)(x-1

13、)=0x1=-1/2x=1(20)6xA2+x-2=0解原方程可化为(3x+2)(2x-1)=0(x+2/3)(x-1/2)=0x1=-2/3x2=1/2这是20道有过程的，还有一些没有过程，只有答案的1)xA2-9x+8=0 答案：x1=8 x2=1(2)xA2+6x-27=0答案：x1=3 x2=-9(3)xA2-2x-80=0答案：x1=-8 x2=10(26)xA2-9x-136=0答案：x1=-8 x2=17(5)xA2-20x+96=0答案：x1=12 x2=8(6)xA2+23x+76=0 答案：x1=-19 x2=-4答案：x1=14 x2=11(7)xA2-25x+154=0

14、(8)xA2-12x-108=0(9)xA2+4x-252=0(10)xA2-11x-102=0(11)xA2+15x-54=0(12)xA2+11x+18=0(13)xA2-9x+20=0(14)xA2+19x+90=0(15)xA2-25x+156=0(16)xA2-22x+57=0(17)xA2-5x-176=0(18)xA2-26x+133=0(19)xA2+10x-11=0(20)xA2-3x-304=0(21)xA2+13x-140=0(22)xA2+13x-48=0(23)xA2+5x-176=0(24)xA2+28x+171=0答案：x1=-6 x2=18答案：x1=14 x2

15、=-18答案：x1=17 x2=-6答案：x1=-18 x2=3答案：x1=-2 x2=-9答案：x1=4 x2=5答案：x1=-10 x2=-9答案：x1=13 x2=12答案：x1=3 x2=19答案：x1=16 x2=-11答案：x1=7 x2=19答案：x1=-11 x2=1答案：x1=-16 x2=19答案：x1=7 x2=-20答案：x1=3 x2=-16答案：x1=-16 x2=11答案：x1=-9 x2=-19(27)xA2-15x-76=0答案：x1=19 x2=-4(28)xA2+23x+126=0 答案：x1=-9 x2=-14答案：x1=-14 x2=5(29)xA2+

16、9x-70=0(30)xA2-1x-56=0(31)xA2+7x-60=0(32)xA2+10x-39=0(33)xA2+19x+34=0(34)xA2-6x-160=0(35)xA2-6x-55=0(36)xA2-7x-144=0(37)xA2+20x+51=0(38)xA2-9x+14=0(39)xA2-29x+208=0(40)xA2+19x-20=0(41)xA2-13x-48=0(42)xA2+10x+24=0(43)xA2+28x+180=0(44)xA2-8x-209=0(45)xA2+23x+90=0(46)xA2+7x+6=0答案：x1=8 x2=-7答案：x1=5 x2=-

17、12答案：x1=-13 x2=3答案：x1=-17 x2=-2答案：x1=16 x2=-10答案：x1=11 x2=-5答案：x1=-9 x2=16答案：x1=-3 x2=-17答案：x1=2 x2=7答案：x1=16 x2=13答案：x1=-20 x2=1答案：x1=16 x2=-3答案：x1=-6 x2=-4答案：x1=-10 x2=-18答案：x1=-11 x2=19答案：x1=-18 x2=-5答案：x1=-6 x2=-1(47)xA2+16x+28=0 答案：x1=-14 x2=-2(70)xA2+13x+30=0答案：x1=-3 x2=-10(49)xA2+13x-14=0答案：x

18、1=1 x2=-14(50)xA2-23x+102=0答案：x1=17 x2=6答案：x1=-16 x2=11(51)xA2+5x-176=0(52)xA2-8x-20=0(53)xA2-16x+39=0(54)xA2+32x+240=0(55)xA2+34x+288=0(56)xA2+22x+105=0(57)xA2+19x-20=0(58)xA2-7x+6=0(59)xA2+4x-221=0(60)xA2+6x-91=0(61)xA2+8x+12=0(62)xA2+7x-120=0(63)xA2-18x+17=0(64)xA2+7x-170=0(65)xA2+6x+8=0(66)xA2+1

19、3x+12=0(67)xA2+24x+119=0(68)xA2+11x-42=0答案：x1=-2 x2=10答案：x1=3 x2=13答案：x1=-20 x2=-12答案：x1=-18 x2=-16答案：x1=-7 x2=-15答案：x1=-20 x2=1答案：x1=6 x2=1答案：x1=13 x2=-17答案：x1=-13 x2=7答案：x1=-2 x2=-6答案：x1=-15 x2=8答案：x1=17 x2=1答案：x1=-17 x2=10答案：x1=-4 x2=-2答案：x1=-1 x2=-12答案：x1=-7 x2=-17答案：x1=3 x2=-14(71)xA2-24x+140=0

20、答案：x1=14 x2=10(72)xA2+4x-60=0 答案：x1=-10 x2=6(73)xA2+27x+170=0答案：x1=-10 x2=-17 (74)xA2+27x+152=0 答案：x1=-19 x2=-8(75)xA2-2x-99=0(76)xA2+12x+11=0(77)xA2+17x+70=0(78)xA2+20x+19=0(79)xA2-2x-168=0(80)xA2-13x+30=0(81)xA2-10x-119=0(82)xA2+16x-17=0(83)xA2-1x-20=0(84)xA2-2x-288=0(85)xA2-20x+64=0(86)xA2+22x+105=0(87)xA2+13x+12=0(88)xA2-4x-285=0(89)xA2+26x+133=0(90)xA2-17x+16=0答案：x1=11 x2=-9答案：x1=-11 x2=-1答案：x1=-10 x2=-7答案：x1=-19 x2=-1答案：x1=-12 x2=14答案：x1=3 x2=10答案：x1=17 x2=-7答案：x1=1 x2=-17答案：x1=5 x2=-4答案：x1=18 x2=-16答案：x1=16 x2=4答案：x1=-7