Notation
w,x,y,z are all just primary statements
"+" is the OR logical operator
what looks like two or more statements being multiplied is actually the AND operator
The complement or prime notation indicates the statement has been negated
"=" indicates logical equivalence
My Work
1) $w'x'z' + xy'z + wx$ (premise)
2) $w'x'z'(y'+y) + xy'z + wx$ (By Complement Law and Identity Law)
3) $w'x'y'z' + w'x'yz' + xy'z + wx$ (By Distributive Law)
4) $w'x'y'z' + w'x'yz' + xy'z + wx(y' + y)$ (By Complement Law and Identity Law)
5) $w'x'y'z' + w'x'yz' + xy'z + wxy' + wxy$ (By Distributive Law)
My Question
I feel I'm very close, but I can't think of a way to change $wxy'$ into $wxy'z'$. I tried ANDing it by $z'+z$ but that creates an extra compound statement that I don't know how to deal with. Can anyone give me a hint as to how to transform $wxy'$ into $wxy'z'$ or suggest another way to finish my proof?