用适当的方法解下列方程:(1)(3x-1) 2 =(x+1) 2 ;(2)2x 2 +x- 1 2 =0;(3)用配方

2025-03-31 12:52:49
推荐回答(1个)
回答1:

(1)将方程(3x-1) 2 =(x+1) 2 移项得,
(3x-1) 2 -(x+1) 2 =0,
∴(3x-1+x+1)(3x-1-x-1)=0,
∴4x(2x-2)=0,
∴x(x-1)=0,
解得x 1 =0,x 2 =1.

(2)∵2x 2 +x-
1
2
=0,
可得,a=2,b=1,c=
1
2

∴x=-
1
4
±
5
4


(3)∵x 2 -4x+1=0,
∴(x-2) 2 =3,
解得x 1 =2+
3
,x 2 =2-
3


(4)设x 2 +x=y,则y 2 +y=6,y 1 =-3,y 2 =2,
则x 2 +x=-3无解,
∴x 2 +x=2,
解得x 1 =-2,x 2 =1.