For the equation below, of Van der Waal form: $\left(P+\frac{n^{2}a}{V^{2}}\right)(V-nb)=nRT$
Determine the partial derivatives; $\Bigl(\frac{\partial V}{\partial T}\Bigr)_{P,n} \text{and } \Bigl(\frac{\partial P}{\partial V}\Bigr)_{T,n}$
Where $a,b, n, R$ are constants.
This is what I've done so far for one of the partial derivatives. I dont know what else to do from here, sorry. $P=\frac{nRT}{V-nb}-\frac{n^{2}a}{V^{2}}$
$\frac{\partial P}{\partial V}=-\frac{nRT}{(V-nb)^2}+\frac{2n^{2}a}{V^{3}}$