(1)3x2-15=0 (2)x2+4x-6=0 (3)2x2-7x+3=0 (4)(x+2)2-10(x+2)+24=0.

问题描述:

(1)3x2-15=0
(2)x2+4x-6=0
(3)2x2-7x+3=0
(4)(x+2)2-10(x+2)+24=0.

(1)3x2-15=0,
变形得:x2=5,
解得:x1=

5
,x2=-
5

(2)x2+4x-6=0,
移项得:x2+4x=6,
配方得:x2+4x+4=10,即(x+2)2=10,
开方得:x+2=±
10

则x1=-2+
10
,x2=-2-
10

(3)2x2-7x+3=0,
分解因式得:(2x-1)(x-3)=0,
可得2x-1=0或x-3=0,
解得:x1=
1
2
,x2=3;
(4)(x+2)2-10(x+2)+24=0,
分解因式得:(x+2-4)(x+2-6)=0,
可得x+2-4=0或x+2-6=0,
解得:x1=2,x2=4.