Answer:
Equation: 12 + 3x = 30
Solution: x = 6
Explanation:
12 + 3x = 30
X stands for how many hours she rented it for. You want to solve for x, so get x by itself.
12 + 3x = 30
-12 -12
---------------------
3x = 18
Divide both sides by 3
3/3x = 18/3
x = 6