Question

Evaluate 9³ - 5³ - 4^{3 .}

Answer 1

We know that if a + b + c = 0 then a³ + b³ + c³ = 3abc

a = 9, b = -5, c = -4
9 + (-5) + (-4) = 0

$\therefore$ 9³ - 5³ - 4³ = 9³ + (-5)³ + (-4)³
= 3(9)(-5)(-4)
= 540