Could you please complete some provided examples of expressing in sigma notation? (Pre-Cal stuff)?

Question

(As given)

a)3 + 5 + 7 + 9 + 11 ... + 51

b) 20 + 18 + 16 + ... +(-8) + (-10)

You can just tell me what is on top of, to the right of, and under the squiggly line thing. Ex. For a), 24 is above.

PLEEEZE HAAAAAAAAAAAAAAAAAAAAAALPPPPP

Answer 1

for a) n=3 is under and to the right is n+2

for b) 15 is on top n = 20 is on the bottom and n-2 is on the right

I'm pretty sure that's what it is after integrals i kinda forgot these haha  

Answer 2

a) from n=1 to n=25, 2n+1

b) from n=-11 to n=4, -2n-2