Question

if x=5-cube root of 25 - cube root of 5. find x^3-15 *x^2-60x + 40

Answer 1

here we used
(a+b)^3= a^3+b^3+3ab(a+b)
and
(a-b)^3=a^3-3a^2b+3ab^2-b^3
formula