(b) Find the equation of the level curve which passes through the point (x, y) = (3, 4).(c) Sketch the cross-section of the surface in the xz plane.(d) Sketch the surface S.Let f : R2 - R be given by f(x, y) =6 - Vx2+yz and let S be the surface given by z = f(x, y). (a) Find the equation of the level curve corresponding to z = 2, and sketch the level curve