如下图所示
(X-12)÷3=(X-4)÷44(X-12)=3(X一4)4X-48=3x-124X-3X=48-12X=36
(x-3*4)/3=(x-4*1)/44x-12*4=3x-124x-3x=12*(4-1)x=12*3x=36