Question

3 3 3
without actually calculating the cubes, find the value of 30 + 20 - 50

Answer 1

(30)3+ (20)3+ (-50)3

∵ (30) + (20) + (-50) = 0

Using identity, if x + y + z = 0, then x3 + y3 + z3 = 3xyz.

= 3 × (30)× (20)× (-50) = -90,000 ...(answer)