Answer:
2x+8
Explanation:
Here, you have to find the similar sides. x and x are both the same thing, while 3 and 5 are both integers (whole numbers).
You add the similar sides together, then that is your answer.
x + x= 2x, and 3+5= 8.
Note: Just because I said that x and x are the same doesn't mean that you can just add random numbers together in other questions.