Find the sum of (3x + 2y) + (3y - 2x)

Since you are adding, the parentheses don't matter here. Rewrite it as 3x + 2y + 3y - 2x. Then, you combine like terms, or terms with the same variable. So, 3x - 2x = 1x, or just x, and 2y + 3y = 5y. That means that your final answer is = x + 5y

1x + 5y, you subtract 2x from 3x because they have the "like" term of x and you add 2y and 3y because they have the "like" term of y