Answer:
-9
Explanation:
We are summing the 3rd 4th and 5th terms because k goes from 3 to 5
The third term is
-2(3) +5 = -6+5 = -1
The fourth term is
-2(4) + 5 = -8+5 = -3
The fifth term is
-2(5) +5 = -10 +5 = -5
Add these 3 terms together
-1+-3+-5 = -9