7. (a) Find the best affine approximation of the function f : R3 - R defined by: f (x, y, z) = aery - xy - 22, at the point p = (1, 1, 1). g(x, y, z) = (2e - 1)x+ (e -1)y - 2z - 2e + 2 (b) Now define h : R2- Rash(x, y) = f(x, y, 0) and find the non-parametric equation of the tangent of the level curve of h at p = (1, 1). y = (1-2e)x+3e-2 e