问题
解答题
(1)x2-2x-2=0;
(2)(x+3)2-x(x+3)=0.
答案
(1)x2-2x=2,
x2-2x+1=3,
(x-1)2=3,
x-1=±
,3
x=1±
,3
∴x1=1+
,x2=1-3
;3
(2)(x+3)(x+3-x)=0,
3(x+3)=0,
∴x=-3.
(1)x2-2x-2=0;
(2)(x+3)2-x(x+3)=0.
(1)x2-2x=2,
x2-2x+1=3,
(x-1)2=3,
x-1=±
,3
x=1±
,3
∴x1=1+
,x2=1-3
;3
(2)(x+3)(x+3-x)=0,
3(x+3)=0,
∴x=-3.