1. The problem statement, all variables and given/known data f(x,y)=xy+(144/x)+(12/y) f has a relative minimum at ( , , ) 2. Relevant equations Partial derivatives 3. The attempt at a solution fx=y-(144/x^2) fy=x-(12/y^2) I setted these to zero. Multiplies both sides so there is no fraction. Came out to be something like~~~ x2y-144=0 xy2-12=0 then did the factoring stuff and got x2-12xy2=0 This tells me that the critical point is (0,0), but this is the wrong answer. PLEASE TELL ME WHAT I AM DOING WRONG. THANK YOU SO MUCH TO THOSE WHO HELP. THIS FORUM IS HELPING ME BECOME A BETTER MATHMATICIAN AND THEREFORE, MY TEST GRADES ARE GOING UP. THANK YOU.