1 point) Let (,) be a function of two variables. Let (,)=(,), and (,)=H(,). Find ′(x) for each of the following cases (your answers should be written in terms of and H). (a) (x)=(x,2): then ′(x)= G(x,2) (b) (x)=(5,x): then ′(x)= H(5,x) (c) (x)=(x, x): then ′(x)= G(x, x)+H(x, x) (d) (x)=(5x, x5): then ′(x)= 5xG(5x, x^5)+5xH(5x, x^5)