$\displaystyle \frac {5x^{3a} + 5x^{2a} y^a}{x^{2a} - y^{2a}} = \frac {5x^{2a}}{x^a-y^a}$ right?

$\displaystyle \frac {m^3 + n^3}{mp-mq-np+nq} \div \frac {mn-m^2-n^2}{mp-mq+np-nq}$ $\displaystyle \Longrightarrow \frac {(m+n)(m^2-mn+n^2)}{(p-q)(m-n)} \cdot \frac{(p-q)(m+n)}{mn-[(m+n)(m-n)]}$ $\displaystyle \Longrightarrow \frac {m^2 -mn + n^2}{m-n} \cdot \frac {m+n}{mn-(m-n)}$ $\displaystyle = \frac {m^3+n^3}{-m^2+m^2n-mn^2+n^2}$ Did I do this right?