Verified answer

Normally, the sum of x^2 terms, however is it possible to take the summation of x alone, THEN square the result. However that would normally be written as (Σx)², the way you have written it I would ASSUME it to mean Σ(x²), since, in general, if you DON'T place parenthesis for the exponential operator, it is assumed that it is tied to the term immedietly preceding it, and ONLY that term. I.E. given xy² we assume it is x * y², not (xy)²

Yes it does

Add the squares of x

Sum of the x² terms.

it means the first

the second would be (Σx)²

The notation isn't clear, but most likely it is the sum of the squares.

Σ(x²)