Question

Can I get some help solving this problem? Thanks!

Answer 1

See below.

Explanation:

Calling `S_n = sum_(k=1)^n (a k^2+b k + c) = a(n(n+1)(2n+1))/6+b(n(n+1))/2+n c`

we need

`S_5`

so you get the result making

`a = 0.17, b = -1.02, c= 6.67, n=5`