1. The problem statement, all variables and given/known data

Let f(x,y) = 5y^(2)-(2x^(2)+xy)

Then an implicit equation for the tangent plane to the graph of f at the point (0,-2) is

3. The attempt at a solution

I understand that I should take the derivative to find the gradient vector. For the derivative, I get <-4x-y,10y-x>.

I plug in (O,-2) and get <2,-20>.

My question is, what should I do to put this into implicit form??

Thanks!