Boolean Algebra- having trouble solving

[photonxyz]

Homework Statement

AB + (A' + B')C + AB

Homework Equations

I've simplified many problems, but this one is giving me trouble. I know the answer is AB + C, but for some mental reason, I can't seem to come to that answer.

The Attempt at a Solution

STEP 1: AB + A'C + B'C + AB
STEP 2: AB + A'C + B'C <-- AB + AB = AB
STEP 3: not sure where to go from here...

ANSWER= AB + C


Thanks for any help :)

 

[Nissen, Søren Rune]

If
AB + A'C + B'C

Then
AB + A'BC + AB'C + A'B'C

Then
AB + C(A'B + AB' + A'B')

It should be obvious that AB + A'B + AB' + A'B' = 1 but how to reduce down to AB + C, I don't know.

 

[photonxyz]

Ok, I figured out the answer... you need to work backwards, as follows;



Original Equation --- > AB + (A' + B')C + AB

STEP 1: AB + (A' + B')C + AB
STEP 2: AB + (A' + B')C <--- AB+AB=AB, so one AB is removed
STEP 3: AB + (AB)'C <--- On this step you took a step backwards
Step 4: AB+C <--- Now, according to demorgans theorem, 11, you ca cancel the AB'

Answer AB+C

Tough one...