1. The problem statement, all variables and given/known data Find the equation of the tangent plane at (2,3,2) to the surface below. x^2 + y^2 - xyz = 1 The question asks me to do this in two way, one is to view the surface as the graph of a function of two variables z = g(x,y). and the other one is to view the surface as a level surface for a function f(x,y z). 2. Relevant equations 3. The attempt at a solution For the first part, I already got an answer of z = (-x+y+5)/3, and so the answer to the second one I assume is x-y+3z-5 = 0. but why is it wrong? am I doing something wrong here?