问题
解答题
解方程:
(1)2x2-4x-1=0;
(2)3x(x+2)=x+2.
答案
(1)2x2-4x-1=0
x2-2x-
=01 2
x2-2x+1=
+11 2
(x-1)2=3 2
∴x1=1+
,x2=1-6 2
;6 2
(2)3x(x+2)=x+2
(x+2)(3x-1)=0
∴x+2=0或3x-1=0,
∴x1=-2,x2=
.1 3
解方程:
(1)2x2-4x-1=0;
(2)3x(x+2)=x+2.
(1)2x2-4x-1=0
x2-2x-
=01 2
x2-2x+1=
+11 2
(x-1)2=3 2
∴x1=1+
,x2=1-6 2
;6 2
(2)3x(x+2)=x+2
(x+2)(3x-1)=0
∴x+2=0或3x-1=0,
∴x1=-2,x2=
.1 3