Answer:
The answer is C.
Step-by-step explanation:
You add,, you don't multiply. Both A and B are not choices.
One of C or D is correct.
That r should be an x according to the attachment.
The answer is add 1 to both sides.
3x - 1 = 7
+1 +1
3x = 8
So you are adding 1 to both sides. The answer is C
