Help with statistics problem

Question

Problem : ∑⁴_{i=2 (x}²+3)

I don't understand why the solution is:

(2²+3) + (7²+3) + (1²+3)

I don't understand how we get 7² followed by 1².

Thanks for your help!!

Answer 1

sum as x is 2, 3 and 4 = (2^2 + 3) + (3^2 +3) + (4^2 +3) = 7 +12 +19 = 38

Maybe that (2^2 + 3) + (7^2 +3) + (1^2 +3) is a solution to a different but similar problem?