**Решение:**
1) (27x^3 - y^3 = (3x)^3 - y^3 = (3x - y)(9x^2 + 3xy + y^2))
2) (25a^3 - ab^2 = a(25a^2 - b^2) = a(5a - b)(5a + b))
3) (-3x^2 - 12x - 12 = -3(x^2 + 4x + 4) = -3(x + 2)^2)
4) (3ab - 15a + 12b - 60 = 3a(b - 5) + 12(b - 5) = (3a + 12)(b - 5) = 3(a + 4)(b - 5))
5) (a^4 - 625 = (a^2)^2 - (25)^2 = (a^2 - 25)(a^2 + 25) = (a - 5)(a + 5)(a^2 + 25))