A student was asked to find an equation for the plane that is tangent plane to the surface at the point $\displaystyle{ (x,y) = (3,1) }$. The student’s answer was

1. At a glance, how do you know this is wrong? What mistakes did the student make? Select all that apply.
   The (x - 3) and (y - 1) should be x and y.
   The 8 should not be in the answer.
   The answer is not a linear function.
   The partial derivatives were not evaluated at the point.
   All of the above
2. Find a correct equation for the tangent plane.