Question

初二数学方程题(要过程)

Answer 1

(1)
196x²-1=0

196x²=1

x²=1/196

x=+-1/14

(2)(X-3)²+2X(X-3)=0(问一下这里2与（X-3）之间是未知数吗？就按未知数做了！）

x²-6x+9+2x²-6x=0

3x²-12x+9=0

x²-4x+3=0

(x-1)(x-3)=0

x=1或x=3

(3)4/5(X+2)²=80

(x+2)²=100

x+2=+-10

x1=8
x2=-12

(4)3X²-6X=-3

x²-2x+1=0

(x-1)²=0

x=1

(5)x²+10x+9=0

(x+1)(x+9)=0

x1=-1
x2=-9

(6)2x²+1=3x

2x²-3x+1=0

(2x-1)(x-1)=0

x1=1/2
x2=1

(7)3x²-4x+2=0

x²-4/3
x+2/3=0

(x-2/3)²=4/9-2/3=-2/9

无解

(8)x²-7x-1=0

（x-7/2)²=1+49/4

x-7/2=+-(√53)/2

x1=7/2+(√53)/2
x2=7/2-(√53)/2