Question

simplify the expression (2x-5y)+(x+y)

Answer 1

(2x - 5y) + (x + y)
You can take away the parentheses.

2x - 5y + x + y
Group up like-terms.

2x + x - 5y + y
Simplify.

3x -4y

Answer 2

(2x-5y)+(x+y) add x and y values because x by itself is considered to be 1x, and y by itself is consided to be 1y. 
(3x-6y) then you should get something like this