Question

(-22) cube + (-15) cube + 7 cube​

Answer 1

Given :-

(-22)³ + (15)³ + (7)³

Here we can use algebraic identity which is a³ + b³ + c³ - 3abc = 0

By shifting -3abc to the RHS, we get

» a³ + b³ + c³ = 3abc

Now,

Here a = -22, b = 15 and c = 7

Therefore (-22)³ + (15)³ + (7)³ :-

= 3(-22)(15)(7)

= -66 × 105

= -6930 Final answer

VERIFICATION :-

LHS -

= (-22)³ + (15)³ + (7)³

= -10648 + 3375 + 343

= -10648 + 3718

= -6930

RHS :-

= -6930

Hence verified!

You can also solve simply by finding their cubes and then adding them. But using identity makes the sum a lot easier and also save time.