Question

Prove that (x+y)^3 -(x-y)^3-6y(x^2-y^2)=8y^3
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Answer 1

this solution will help u

Answer 2

Use

${(x - y)}^{3 } = {x}^{3} - {y}^{3} - 3xy(x - y)$

${(x + y)}^{3} = {x}^{3} + {y}^{3} + 3xy(x + y)$

You'll get it!