1) x(y + 5) + 5 + y = x(y + 5) + (y + 5) = (y + 5)(x + 1)

2)  b - c - a(c - b) = b - c + a(b - c) = (b - c)(1 + a)

3)  ab - ac + 4c - 4b = a(b - c) + 4(c - b) = a(b - c) - 4(b - c) = (b - c)(a - 4)