# Boolean algebra problem

1. Sep 19, 2009

### Ownaginatious

Okay, so I'm stuck at a step of a much bigger problem where I have to simplify a boolean function.

1. The problem statement, all variables and given/known data

Here is where I'm stuck, I have to change the left hand side to the right hand side. How do I prove this with the rules of boolean algebra?

CA + CB + B'A = CB + B'A

2. Relevant equations

3. The attempt at a solution

The above is as far as I've gotten (as I said, this was taken from a bigger problem).

Can someone please show me the steps that will change the left hand side of the equation to the right? According to truth tables, they are infact equal.

2. Sep 19, 2009

### elduderino

This appears wrong as the expression you wrote implies A+B=B, which is not true for a complete truth table.

3. Sep 19, 2009

### Ownaginatious

Well, according to this truth table, it's right:

http://img170.imageshack.us/img170/3023/truth.png [Broken]

I can't figure out how to prove this algebraically though.

Last edited by a moderator: May 4, 2017