Solve for $a$
$V=2(ab+bc+ca)$
$$\left(\frac{V}{2}\right)=ab+bc+ca$$ $$\left(\frac{V}{2}\right)-bc=ab+ca$$ $$\dfrac{\left(\frac{V}{2}\right)-bc}{b+c}=2a$$ $$\frac{\left(\frac{V}{2}\right)-bc}{2b+c}=a??$$ I honestly do not know what to do with this problem. And I think I may have messed up when I divided by $b+c$. Any pointers. please, no answers. Only generalized hints.