Question

Without actually calculating the cubes, find the value of (28) ³+(-15) ³+(-13) ³

Answer 1

U can do this by using the formula.... a³+b³+c³=(a+b+c)(a²+b²+c²-ac-bc-ab)+3abc

Answer 2

X+y+z=0
X^3+y^3+z^3-3xyz
X^3+y^3+z^3=3xyz
So…28^3+(-15)^3+(-13)^3=3×28×-15×-13
28^3+-15^3+-13^3=16380