Answer: Subtract -3 from both sides, r = 0
Explanation:
When solving an algebraic equation like this one, we want to isolate the variable we are solving for. In this case, that is r.
To do so, we will subtract -3 from both sides (adding 3 will cancel out the -3 on the left, leaving r alone).
-3 + 3 = 0
r = 0