5ax+5bx+3ay+3by =5x(a+b)+3y(a+b) =(5x+3y)(a+b) x³-x²+x-1 =(x³-x²)+(x-1) =x²(x-1)+(x-1) =(x-1)(x²+1) x²-x-y²-y =(x²-y²)-(x+y) =(x+y)(x-y)-(x+y) =(x+y)(x-y+1)
