idk

find the sum of (3x - 5y) and (x+y)

This is:
(3x - 5y) +(x+y)

You can take out the parentheses because (3x - 5y) and (x+y) are both being multiplied by a positive 1.
=(3x - 5y) + x + y
=3x - 5y + x + y
Now just add/subtract.
3x+x -5y+y

=4x -4y