Calculate and simplify dy dx (4x2 + y', -5 xy) in terms of the partial derivatives of first and second order of f, given that these partial derivatives are continuous. . . . Be careful not to repeat minus signs that are already printed outside the boxes. Remember to use the continuity of f12(u, v) and f21 (u, v). dy dx F (4x2 + 12, - 5 xy) = avdyflu, V) = 12 (4, v) + 1 (u, v) - (D) f12 (u, v) + $2z (4, v) where u = 4x + y and v= -5 xy. (In the various boxes, type the appropriate expressions or numbers.)