$\displaystyle p^2x^2 + q^2 y^2-qx-py+ (\frac{p}{q}-\frac{q}{p})^2 +2 = 0, find
(p^2x+q^2y)-p-q.
$
Thank you.
just expand the expression then isolate that unit that you are supposed to find, just like you would isolate y or x or any other single variable. except here its just a little more complicated, but im sure you've got it sorted. its like rearranging the equation...
have fun