Помогите решить 3 и 4 задание

3)
$\frac{4a^2-1}{a^2-9}: \frac{6a+3}{a+3} = \frac{4a^2-1}{(a-3)(a+3)}: \frac{6a+3}{a+3}= \frac{(2a-1)(2a+1) * (a+3)}{(a-3)(a+3) * 3(2a+1)} = \frac{2a-1}{3(a-3)}$

4)
$\frac{p-q}{p}*( \frac{p}{p-q}+ \frac{p}{q} )= \frac{p-q}{p}*( \frac{qp+p(p-q)}{q(p-q)} )= \frac{p-q}{p} *( \frac{qp+p^2-pq}{q(p-q)}) =$ $\frac{p-q}{p}*( \frac{p^2}{q(p-q)} ) = \frac{(p-q)*p^2}{p*q(p-q)} = \frac{p^2}{pq} = \frac{p}{q}$