Find the indicated sum. Show your work.

Question

4 k=1 (-1)^k(k+11)
Inbetween the 4 and k , Theres a backwards 3 sign

Answer 1

That's a sigma

4
∑ (-1)^k (k+11)
k=1

= (-12)+(13)+(-14)+(15)
= 2

Answer 2

Thank you :)