Answer:
-515
Step-by-step explanation:
In this example the first value is −15 and every value afterwards is 20 less.
After substituting these values to above formula, we obtain:
All we have to do is add 25 twenties or 25 x 20 = 500 and -15 - 500 = -515
No one is going to do all this for 5 points...
