What is this answer because i don't know how to do it

You are solving for n. First you want to get n by itself on one side of the equal sign. To do this you need to get rid of the -5, so you add it to both sides.

13 + 5 = n - 5 + 5

18 = n

Hope this helps!

So you need to solve for x. To do so you need to isolate the variable first. This is what you do.

13 = x - 5
You add 5 to both sides to get x by itself.
18 = x
So now lets check our work by plugging in the variable! :)
13 = 18 - 5
13 = 13
It is a solution so 18 is your answer.
I hope this helps love! :)