# Thread: I don't understand this boolean simplification - basic boolean laws

1. ## I don't understand this boolean simplification - basic boolean laws

I am trying to simplify x’y’z’ + x’yz + xy’z’ + xy’z + xyz
from using online calculators, i think the sum of products answer should be
y’z’ + yz + xy'

but I am only getting as far as here:
= x’y’z’ + x’yz + xy’z’ + xy’z + xyz
= y’z’(x’ + x) + yz(x’ + x) + xy’z
= y’z’ + yz + xy’z

What basic Boolean rule says that I can take off that z?
And why can't I do something like
= y'z' + z(y + xy')
= y'(z'+z)(y + xy')
= oh man... i have been looking at this for hours

Can someone explain this to me?

- Dave

2. ## Re: I don't understand this boolean simplification - basic boolean laws

I was able to figure it out myself. For anyone else trying to do something like this, check out this video: https://www.youtube.com/watch?v=59BbncMjL8I

- Dave

3. ## Re: I don't understand this boolean simplification - basic boolean laws

What was your final answer to that problem because I'm working on the same thing!