解方程: (1)x2-2x=5; (2)(x+1)(x-1)+2(x+3)=8.

问题描述:

解方程:
(1)x2-2x=5;             
(2)(x+1)(x-1)+2(x+3)=8.

(1)配方得(x-1)2=6,
x-1=±

6

则x1=1+
6
,x2=1-
6

(2)原方程可化为x2+2x-3=0,
(x+3)(x-1)=0,
可得x+3=0或x-1=0,
则x1=-3,x2=1.