Boolean algebra show that LHS = RHS

Question

Prove the following equality with the laws of boolean algebra:

$$wx + w'y + xyz = wx + w'y$$

Ok this should not be to hard but I can't see it. Anyone?

My attempt:

$wx + w’y + xyz$

Using the rule B18

$wx + w’y + xy + xyz$

Using the rule B16

$wx + w’y + xy \neq wx + w’y$

Answer 1

Note that $$w x = w x(1+yz) = w x + w xyz,$$ and $$w' y = w' y(1+xz) = w' y + w' xyz.$$ Therefore, $$wx + w'y = ?$$

---

Alternative solution: Using B18, we have $$wx+w'y+xyz = wx + w'y + \underbrace{xy + xyz}_{B16} = wx + w'y+xy = wx+w'y.$$