问题
解答题
用适当方法解方程
(1)(2x-1)2=9;
(2)x2+3x-4=0;
(3)(x+4)2=5(x+4);
(4)(x-2)(x-5)=-2;
(5)2x2-10x=3;
(6)(3x+5)(3x-5)+6x=-26.
答案
(1)(2x-1)2=9,
2x-1=3或2x-1=-3,
解得:x1=2,x2=-1;
(2)因式分解,得:(x+4)(x-1)=0,
x+4=0或x-1=0,
解得:x1=-4,x2=1;
(3)原方程可化为:(x+4)(x+4-5)=0,
x+4=0或x-1=0,
解得:x1=-4,x2=1;
(4)整理,得:x2-7x+10=-2,
x2-7x+12=0,
(x-3)(x-4)=0,
解得:x1=3,x2=4;
(5)移项,得:2x2-10x-3=0,
a=2,b=-10,c=-3,
b2-4ac=100+24=124>0,
x=
=5±10±2 31 4
;31
解得:x1=5+
,x2=5-31
;31
(6)原方程整理,得:9x2-25+6x=-26,
9x2+6x+1=0,
(3x+1)2=0,
解得:x=-
.1 3