一元二次方程100道过程 九年级一元二次方程题

(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. 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 .

X^2-X-6=0 2X^2-3X-2=0 -3X^2+6X=2 4X^2-4X+1=0 X^2-2X+3=0 -X^2-2X+8=0 X^2-X-2=4 2X^2-3X+1=0 -3X^2+4X+4=0 4X^2-11X-3=3 x^2-2x-3=04x^2-1=05x^2-3x+2=0-x^.

(1)3x=0 (2)-3x=2 (3) (4) (5)-3x-5=0 (6)-3x+5=-2 (7)2=-3x+5 (8)2x+5=3x (9)2x-5=-3x (10)-2x-5=

x^2-2x-80=0 答案:x1=-8 x2=10 (x+8)(x-10) (4)x^2+10x-200=0 答案:x1=-20 x2=10 (x+20)(x-10) (5)x^2-20x+96=0 答案:x1=12 x2=8 (x-12)(x+8) (6)x^2+23x+76=0 答案:x1=.

1) 66x+17y=3967 25x+y=1200 答案:x=48 y=47 (2) 18x+23y=2303 74x-y=1998 答案. 14x+y=966 答案:x=69 y=62 (99) 84x+53y=11275 70x+y=6790 答案:x=97 y=59 (100.

解:(1)x²=1/196 则x=-14或14 (2)(X-3)^2+2X(X-3)=0变形得(X-3)(3-3X)=0 则X=3或1 (3)4/5(X+2)^2=80 变形得(X+2)^2=64 则x=6或-8 (4)3X^2-6X=-3 变形3(x-1)^2=0得x=1 (5)x^2+10x+9=0 因式分解(x+1)(x+9)=0得x=-1或-9 ( 6)2x^2+1=3x 因式分解(2x-1)(x-1)=0得x=1/2或1 (7)3x^2-4x+2=0 直接套公式即可 (8)x^2-7x-1=0 同(7)

x的平方 x-12=0 (x 4)(x-3)=0 x=-4,x=3 x的平方-4x-12=0 (x-6)(x 2)=0 x=6,x=-2 (x的平方-. 6x 11x-2=0 (6x-1)(x 2)=0 x=1/6,x=-2 用换元法解方程: x的4次方-x的平方-6=0 解:设x.

5(x+8)-5=6(2x-7) 解:5x-40-5=12x-42 5x-35=12x-42 77=7x x=11 2(2x+1)-10x-1=6 解:4x+2-10x-1=6 -6x+1=6 6-1=6x 5=6x x=5/6 6(12+x)=10(12-x) 解:72+6x=120-10x 10x+.

x²+4x+1=6 4x²-4x=0 x²+6x+1=8 x²-4x+4=16 x²+8x=0

(11)x^2+15x-54=0 答案:x1=-18 x2=3 (x+18)*(x-3)=0(12)x^2+11x+18=0 答案:x1=-2 x2=-9(x+2)*(x+9)=0 (13)x^2-9x+20=0 答案:x1=4 x2=5(x-4)*(x-5)=0 (14)x^2+19x+90=0 .