3 (2x+2y) - (x-7y) multiply and simplify

6x+6y-x+7y

6x-x+6y+7y

5x+13y

Now, I would get rid of the parenthesis, also remember a double negative is a positive.

6x + 6y-x+7y

Now add or subtract like terms.

5x+13y

You can check this by put x as 1 and y as 2, and putting it in to both equation. (I do this, you don't have to)

3 (2 + 4) - (1 - 14)

18 + 13 = 31

5 + 26 = 31

So it would be 5x+13y.