Question

simplify (x-2/3y)³- (x+2/3y)³

Answer 1

In the picture are all possible results.

Answer 2

$\textbf{Answer:}$

$(x - \frac{2}{3}y {})^{3} - (x + \frac{2}{3}y {})^{3} \\ \\ = ( {x}^{3} - (\frac{2}{3} {y})^{3} - 3(x)( \frac{2}{3}y)(x - \frac{2}{3}y) \\ \\ = {x}^{3} + (\frac{2}{3} {y})^{3} + 3(x)( \frac{2}{3}y) \: (x + \frac{2}{3}y) \\ \\ ( {x}^{3} - \frac{8}{27} {y}^{3} - 2 {x}^{2}y + \frac{4}{3}x {y}^{2}) - ( {x}^{3} + \frac{8}{27} {y}^{3} +2 {x}^{2}y + \frac{4}{3}x {y}^{2}) \\ \\ = - \frac{16}{27} {y}^{3} - 4 {x}^{2}y$

$\textbf{Hope it helps you!}$