Ответ:а) \(3x-xy-3y+y^2=3(x-y)-y(x-y)=(3-y)(x-y)\).б) \(cy-cx+ax-ay-x+y=c(y-x)+a(x-y)-(x-y)=-c(x-y)+a(x-y)-(x-y)=(a-c-1)(x-y)\).