Boolean Identity: (x + yx) = (x + y)(x + z) what is z

Question

In the boolean Identity:

(x + yx) = (x + y)(x + z)

Where does z come from and what does it mean?

Answer 1

I think it should be $$X+YZ=(X+Y)(X+Z)$$. Please check your question once again. Or see the link

https://www.cs.umd.edu/users/meesh/webpages/old-cmsc311/HW/chap2.text

Answer 2

$x=0, 1=>x^2=x=>$ $$ \\x+xy=x^2+xy=x(x+y)=(x+0)(x+y) $$ $=>z=0$