Question

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1/ (x+y)\(^3\) + (x-y)\(^3\)

2/ (3x+1)\(^3\) 

Answer 1

1 \(=x^3+3x^2y+3xy^2+y^3+x^3-3x^2y+3xy^2-y^3\)

\(=2x^3+6xy^2\)

2: \(=27x^3+27x^2+9x+1\)

Answer 2

`1)`\(\left(x+y\right)^3+\left(x-y\right)^3\)

\(=x^3+3x^2y+3xy^2+y^3+x^3-3x^2y+3xy^2-y^3\)

\(=2x^3+6xy^2\)

`2)`\(\left(3x+1\right)^3\)

\(=\left(3x\right)^3+3.\left(3x\right)^2.1+3.3x.1+1^3\)

\(=27x^3+27x^2+9x+1\)