Answer
The Addition Property of Equality states that if $a=b$, then $a+c = b+c$. This property allows like terms to be combined, which is how equations can be added.
Work Step by Step
Example:
$a=2x$, $b=2x$, and $c=3x$
$a + c = b + c$
$2x + 3x = 2x+ 3x$
$5x = 5x$
