# Boolean Algebra AB(A+Bar)=X

1. Feb 3, 2005

### cact

I was just wondering if anyone could lend me some guidence in the boolean equation AB(A+B)= X when the last "B" in the formula has a bar above it.. thanks

2. Feb 3, 2005

### Janitor

If juxtaposition stands for "meet" and + stands for "join," then you can use the distributivity of meet over join to get an expression without any parentheses. Then use that fact that meet and join are each symmetrical so that you can interchange the variables on either side. Then use what you know about thiings such as the meet of a variable with itself, and the meet of a variable with its negation. I think I know what the answer is, but I'll let you take it from here.

3. Feb 3, 2005

### AKG

$$AB(A + \overline{B}) = ABA + AB\overline{B} = AB + A(0) = AB$$