3xy-2x-12y+8=(3xy-12y)-(2x-8)=3y(x-4)-2(x-4)=(x-4)(3y-2)ab-5bc-2a²+10ac=(10ac-5bc)-(2a²-ab)=5c(2a-b)-a(2a-b)=(2a-b)(5c-a)5ax+7ay-5bx-7by=(5ax-5bx)+(7ay-7by)=5x(a-b)+7y(a-b)=(a-b)(5x+7y)x&sup...