fg - 5g + 4f - 20
(g + 4)(f - 5)
xy - 2x - 2 + y
(x + 1)(y-2)
45pq - 27q - 50p + 30
(9q - 10)(5q -3)
9x2 - 3xy + 6x - 2y
(3x + 2)(3x - y)
3n2 + 6np - np - 2p2
(3n - p)(n + 2p)