a ^ 2 +a a^ 3 - a ^ 7 4c ^ 2 -12c^ 4 6) x^ 3 - x ^ 2 x^ 3 - x ^ 2 3m ^ 2 +9m^ 3 5x ^ 5 -15x^ 3

a^2 + a = a(a + 1) a^3 - a^7 = a^3(1 - a^4) 4c^2 - 12c^4 = 4c^2(1 - 3c^2) x^3 - x^2 = x^2(x - 1) 3m^2 + 9m^3 = 3m^2(1 + 3m) 5x^5 - 15x^3 = 5x^3(x^2 - 3)