Answer:
The correct answer to this problem is r = 8.
Explanation:
To solve this problem, we have to remember that our goal is to get the variable (in this case, r) by itself on one side of the equation. To do this, we have to get rid of the -7 on the left side of the equation. Therefore, our first step is to add 7 to both sides of the equation. This gives us:
r - 7 = 1
r - 7 + 7 = 1 + 7
r = 8
Thus, your answer is r = 8.
Hope this helps!