x-5x+6=12x-5x-6=0(x+1)(x-6)=0x=-1或x=6
(x-2)(x-3)=12(x^2)-5x+6=12(x^2)-5x-6=0(x-6)(x+1)=0x1=6,x2=-1
x^2-5x-6=0 (x-6)(x+1)=0 x=6或-1
x^2-5x-6=0(x-6)(x+1)=0x=6或-1
把12移到左边.