1)
10ay-5by+2ax-bx =
= (10ay-5by)+(2ax-bx ) =
= 5y(2a-b) + x(2a-b ) =
= (2a-b)(5y+x )
2)
5x²-5ax-7a+7x =
= (5x²-5ax) + (7x-7a) =
= 5x·(x-a) + 7·(x-a) =
= (x-a)(5x+7)
