3- simplify the following functional expressions using boolean algebra and its identities. list the identity used at each step: a) f(x, y,z) = y(x' + (x + y)') b) f(x, y,z) = x'yz + xz c) f(x, y,z) = (x + y + z') + xy'z' + yz + xyz d) z(w + x)' + w'xz + wxyz' + wxyz e) xlyz' + x){y' +z)