Simplify 8 - {x - (5 + x)}:
Order of operations rules require that you perform work inside parentheses first. Thus, do this first: x - (5 + x) => x - 5 - x => -5.
Now we have the following: 8 - {-5} => 8+5 = 13 (answer)
Please note: To avoid confusion, please separate answer choices, such as 3 13 -2x + 3 -2x + 13, by using commas or by putting each choice on its own new line:
3
13
-2x + 13
I was and still am unsure of what you meant here.