CBSE Notes, Lectures

CBSE - Mathematics - Polynomials

Polynomials

NCERT Exercise Exercise 2.5

If x + y + z = 0, show that x3 + y3 + z3 = 3xyz.

If x + y + z = 0, show that x3 + y3 + z3 = 3xyz.

Answer

We know that,
x3 + y3 + z3 - 3xyz = (x + y + z)(x2 + y2 + z2 - xy - yz - xz)
Now put (x + y + z) = 0,  
x3 + y3 + z3 - 3xyz = (0)(x2 + y2 + z2 - xy - yz - xz) 
⇒ x3 + y3 + z3 - 3xyz = 0

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