Q32

Let $f(w, x, y, z) = \sum {\left(0,4,5,7,8,9,13,15\right)}$. Which of the following expressions are NOT equivalent to $f$? P: $x'y'z' + w'xy' + wy'z + xz$ Q: $w'y'z' + wx'y' + xz$ R: $w'y'z' + wx'y' + xyz+xy'z$ S: $x'y'z' + wx'y'+ w'y$