(fₓ(x,y) = 2x + 3y) and (fᵧ(x,y) = x - 2y).

a) (fₓₓ(x,y) = 2)
b) (fyx(x,y) = 3)
c) (fxy(x,y) = 1)
d) (fyy(x,y) = -2)