Hecc i don't pay attention, anyways what's -15 - (-7) ? ya boi out guys ": ")

So keep -15 change the subtraction sign to an addition sign and change the sign of the second number. So you will end up with -15+7. Then you use the adding rules. So you end up subtracting anyway since the signs are different. So 15-7=8. Keep the sign of the larger number and your answer is -8. (Ignore the negative 22 at the top, I did it wrong the first time.

If your asking how much altogether for 12 performance the answer will be 98,496.