# Boolean Algebra Help

1. Sep 13, 2010

### EEhokie13

1. The problem statement, all variables and given/known data
Simplify the following expressions using Boolean Algebra.

a) A + AB (A or A and B)
b) A'BC + AC (A(not) and B and C or A and C)
c) A'B + ABC' + ABC (A(not) and B or A and B and C(not) or A and B and C)

2. Relevant equations
Some simple boolean algebra rules.
x+1=0
x*x=x
x*x'=0

3. The attempt at a solution

For a, I got the answer of A.
I did:
A(1 + B)
A(1)
= A

For b, I got the answer AC.

I did:
C(A'B + A)
C(0 + A)
= AC

For c, I got the answer AB.
I did:
B(A' + AC' + AC)
B(A' + (A.C') + (A.C))
B(A' + (0) + A)
B(A' + A)
B(A)
= AB

Are my calculations correct or am I completely wrong? Thank you for your help.

2. Sep 13, 2010

### Bill Simpson

Your part b is incorrect. How do you get Not(A) and B == False? What if A were false and B were true?

Your part c is incorrect. You appear to be making the same kind of mistake with A.C'

So it appears you are correctly understanding a number of the things you should, but you are missing at least the one thing you missed twice here.