1) ab - 8a - bx + 8x = a(b - 8) - x(b - 8) = (b - 8)(a - x)
2) ax - b + bx -a = ax + bx - (a + b) = x(a + b) - (a + b) = (a + b)(x - 1)
3) ax - y +x - ay= (ax - ay) - (x - y) = a(x - y) - (x - y) = (x - y)(a - 1)
4) ax- 2bx + ay -2by = (ax + ay) - (2bx + 2by) = a(x + y) - 2b(x + y) =
= (x + y)(a - 2b)