Answer: 3x + 3y - 13xy
Move the numbers so that the ones with the same variable can be together :> ( examples of variables: x,y,xy)
4x - x + 5y - 2y - 13xy
You can only do the math if the those numbers are the same example: 4x - x = 3x they both have variable so u can subtract them ( remember x = 1x a variable by itself has a invisible 1 next to it). 5y - 2y = 3y.
-13xy is the only one with the variable xy so we gotta just leave it alone
This leads to our answer:
3x + 3y - 13xy