Help with Boolean expression simplification with $4$ variables. I've simplified this expression and am unsure if it's completely simplified. If it can be simplified, can you provide me with the answer and the steps/laws taken to do so? Thank you.
$y’(z+x)+z’(xw+x’y)$

No.   That's about as simple as it gets.  
The DNF is $~wxz'+xy'+x'yz'+y'z~$ which is mostly where you are.
