**Решение:**
1) (m^3 + 125n^3 = m^3 + (5n)^3 = (m + 5n)(m^2 - 5mn + 25n^2))
2) (xy^2 - 16x^3 = x(y^2 - 16x^2) = x(y - 4x)(y + 4x))
3) (-5x^2 + 30x - 45 = -5(x^2 - 6x + 9) = -5(x - 3)^2)
4) (7xy - 42x + 14y - 84 = 7x(y - 6) + 14(y - 6) = (7x + 14)(y - 6) = 7(x + 2)(y - 6))
5) (10000 - c^4 = (100 - c^2)(100 + c^2) = (10 - c)(10 + c)(100 + c^2))