Hi guys I know this is a really basic question but after looking at the tutorial and reference I couldn't quite figure out how to solve a nonlinear system of equations. (If this is even possible, I dont know).

I have this:

    lst eqns, vars;

    eqns = D==pow(T,2);

    vars =T;

    ex L = lsolve(eqns,vars);

But lsolve (I guess the l for linear makes it obvious) cannot solve this nonlinear function. Is there another way I can accomplish this? Then I could do something like:
ex ans = L.subs(lst(D==3)); like I would for a linear? Is this even possible? Thanks for any answer! Ginac is a great tool for me so far!