Question

Expand (1-x)^4. Hence find S if S = (1-x^3)^4 - 4(1-x^3)^3 + 6 (1-x^3)^2 - 4(1-x^3) + 1.

Answer 1

S = (1-(1-x^3))^4 = (x^3)^4 = x^12