We are adding like terms for this question. We combine same variables (ex. 5x+8x or 195xy+4xy) and all constants (without variables ex. 5+196).
So the side lengths are 5+x, 5+x, and xy.
We need to added them up for perimeter.
5+x+5+x+xy
Simplify
xy+2x+10
This would be the simplifies form.