please answer (a) ,(b)

13. Do the following two parts: (a) Find the sum-of-products expansion of the Boolean function F(w, x, y, z) that has the value 1 if and only if an odd number of w, x, y, and z have the value 1. (b) Find a Boolean product of Boolean sums of literals that has the value 0 if and only if x = y = 1 and z = 0, x = z = 0 andy = 1, orx = y = z = 0