Question

Value of 28cube+(-15)cube+(-13)cube is?

Answer 1

Answer:

(28)³+(-15)³+(-13)³

take x = 28 , y = -15 , z = -13

we know the algebraic identity,

x³+y³+z³ -3xyz = (x+y+z)(x²+y²+z²-xy-yz-zx)

and we also know that,

If x+y+z = 0 ,then x³+y³+z³ = 3xyz

so here, x+y+z = 28+(-15)+(-13)

= 28 - 28

= 0

so, x³+y³+z³ = 3(28)(-13)(-15)

= 16,380

so 28³+(-15)³+(-13)³ = 16,380

Verify if required

hope it helps......... ☺