The answer would be -7x + 20y
-2x + 3y - 5x - ( -8y ) + 9y
When there are two negative signs one after another, it turns into a positive.
-2x + 3y -5x + 8y + 9y
Now you need to add up all common numbers.
-2x - 5x = -7x
3y + 8y + 9y = 20y
The remaining two numbers don't have a common variable, so they stay separate;
-7x + 20y