c) (x + 3)^3(x – 3)^3;
c) (x + 3)3(x – 3)3;
c) (x + 3)3 ‒ (x – 3)3
= x3 + 3.x2.3 + 3.x.32 + 27 ‒ (x3 ‒ 3.x2.3 + 3.x.32 ‒ 27)
= x3 + 9x2 + 27x + 27 ‒ x3 + 9x2 ‒ 27x + 27
= (x3 ‒ x3) + (9x2 + 9x2) + (27x ‒ 27x) + 27 + 27
= 18x2 + 54.