Ab+ac-ab-4c= 3a-3m-ay+my= 2ax+3by+6ay+bx
1) ac-4c= c(a-4) 2) 3(a-m)-y(a-m)= (3-y)(a-m) 3) 2a(x+3y)+b(3y+x)= (2a+b)(3y+x)