Question 1165308
<pre>
There are thousands of such expressions.  

Some are c, 2a+1, 4b+7, 100c+79, a+b, b+c, thousands more. 

What were the choices you had to pick from that you didn't post?

all you have to know are:

EVEN + EVEN = EVEN
EVEN + ODD = ODD
ODD + EVEN = ODD
ODD + ODD = EVEN

EVEN x EVEN = EVEN
EVEN x ODD = EVEN
ODD x EVEN = EVEN
ODD x ODD = ODD


Edwin</pre>