# Thread: Property Help

1. ## Property Help

I have this problem:
a * (a + b) = a

And I can only use the commutative, distributive, identity, negation properties.

A hint that my teacher gives is to use is
a * a (a + b) = (a + 0) * (a + b)

Can anyone help me?
My teacher doesn't explain it well at all!

2. You have to tell us more about what is going on here.
What is the definition of the operation *?
How does a(a+b) work or what does a(a+b) mean?

3. Originally Posted by Plato
You have to tell us more about what is going on here.
What is the definition of the operation *?
How does a(a+b) work or what does a(a+b) mean?
Whops the hint is actually a * (a + b) = (a + 0) * (a + b)

But I think you got it.

* = and
+ = or

4. This a simple Boolean Algebra.
This proof may or may not fit your text book.
[tex]This a simple Boolean Algebra.
This proof may or may not fit your text book.
$\begin{array}{rcl}
a*\left( {a + b} \right) & = & \left( {a + 0} \right)*\left( {a + b} \right)\quad \mbox{Identity Law} \\
& = & a + \left( {0*b} \right)\quad \mbox{Disributive Law} \\
& = & a + 0\quad \mbox{Null Law}l \\
& = & a\quad \mbox{Identity Law} \\
\end{array}
$