(1)(5-8x)^2=2 (2)x^2+8x=20 (3)3x^2+2x-3=0 (4)(x-1)(x+2)=70

问题描述:

(1)(5-8x)^2=2 (2)x^2+8x=20 (3)3x^2+2x-3=0 (4)(x-1)(x+2)=70
选择适当的方法解方程
(1)(5-8x)^2=2
(2)x^2+8x=20
(3)3x^2+2x-3=0
(4)(x-1)(x+2)=70
55,没金了,对不起了.
要详细过程.

(1)(5-8x)^2=2(8x-5)^2-2=0(8x-5-√2)(8x-5+√2)=0x=(5+√2)/8或x=(5-√2)/8(2)x^2+8x=20x^2+8x-20=0(x+10)(x-2)=0x=-10或x=2(3)3x^2+2x-3=0x^2+2x/3-1=0x^2+2x/3+1/9-1/9-1=0(x+1/3)^2-10/9=0(x+1/3-√10...