When you are asked to simplify an algebraic expression like this, you just have to remember to group "like terms".
Here's a similar expression: 5x + 3y + 8 + 2x - 2y.
Here are the terms in this expression:
"Like" terms are ones that have the same variables with the same exponents (you don't have any exponents, so you don't have to worry about that here).
So 5x and 2x are like terms. Remember that multiplication is implied between the coefficients (5 and 2) and the variable (x). So if you have 5 times something and 2 times the same thing, then you have 7 times the thing.
5x + 2x = (5+2) x = 7x
And similarly, 3y - 2y = (3-2) y = 1y = y. So the simplified version of this expression is 7x + y + 8.
Now you try it with your expression.
Stephen La Rocque.