问题
解答题
(1)解方程:x2+4x-1=0;
(2)解方程:3(x-5)2=2(5-x).
答案
(1) x2+4x=1,
x2+4x+4=1+4,
(x+2)2=5,
x+2=±
,5
∴x1=-2+
,x2=-2-5
.5
(2) 3(x-5)2+2(x-5)=0,
(x-5)(3x-15+2)=0,
∴x1=5,x2=
.13 3
(1)解方程:x2+4x-1=0;
(2)解方程:3(x-5)2=2(5-x).
(1) x2+4x=1,
x2+4x+4=1+4,
(x+2)2=5,
x+2=±
,5
∴x1=-2+
,x2=-2-5
.5
(2) 3(x-5)2+2(x-5)=0,
(x-5)(3x-15+2)=0,
∴x1=5,x2=
.13 3