Question

Fins the value of (15)^3 + (-9)^3 + (-6)^3 , without actually cubing the numbers​

Answer 1

a³ + b³ + c³ + 3abc = ( a + b + c)(a² + b² + c² + ab + bc + ca)

if a + b + c = 0. then a³ + b³ + c³ = 3abc

here a + b + c = 15 + (-9) + (-6)

a + b + c = 15 - 15

a + b + c = 0

so a³ + b³ + c³ = 3abc

15³ + (-9)³ + (-6)³ = 3(15)(-9)(-6)

= 2430

so the answer is 2430