Simplify the following expressions:
1. x + y'
2. z'
3. x' + z'
4. y' + x'y
5. x'z'
1. F(x, y, z) = xy' + xy + xyz' + xyz
2. F(w, x, y, z) = xyz' + xyz' + wyz' + wyz
3. F(w, x, y, z) = y'z' + xyz' + wx'yz + xy'z' + wx'z + x'yz' + w'x'z + x'z'
4. F(w, x, y, z) = wxy + wx'yz' + wxy'z' + wxy'z + w'xy'z + wx'yz
5. F(w, x, y, z) = wx'yz' + wx'y'z' + wx'yz' + wx'yz