5x(x-3)=12-4x
问题描述：
5x(x-3)=12-4x
答
5x(x-3)=12-4x
5x(x-3)+4x-12=0
5x(x-3)+4(x-3)=0
(5x+4)(x-3)=0
x=3或x=-4/5