d) x(x – 1)(x + 1) – (x − 3)(x^2 + 3x + 9).
d) x(x – 1)(x + 1) – (x − 3)(x2 + 3x + 9).
d) x(x – 1)(x + 1) – (x − 3)(x2 + 3x + 9)
= x[(x – 1)(x + 1)] ‒ (x3 ‒ 33)
= x(x2 ‒ 1) ‒ (x3 – 27)
= x3 ‒ x ‒ x3 + 27
= (x3 ‒ x3) ‒ x + 27
= 27 ‒ x.