Question

用因式分解解方程：2x(4x+5)=7

Answer 1

8X方+10X-7=0
（2X-1）（4X+7）=0
X=1/2或X=-7/4
带入验证成立

Answer 2

8x^2+10x-7=0
x^2+5/4x-7/8=0
(x+5/8)^2=7/8+25/64=81/64
x+5/8=±9/8
x=-5/8±9/8
x1=-7/4 x2=1/2