Question

If a + b + 2c = 0, prove that a3 + b3 + 8c3 = 6abc.
-8
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Answer 1

Step-by-step explanation:

a+b+2c=0

a+b=-2c

Cubing on both sides

(a+b)3=(-2c)3

a3+b3+3ab(a+b)=-8c3

a3+b3+3ab(-2c)= -8c3

a3+b3-6abc=-8c3

a3+b3+8c3=6abc