Question

Help please I need it now!

Answer 1

Answer:
`\sum^(7)_(n=1) (-2+9n)`

Explanation:

This is an arithmetic series with first term 7 and common difference 9, so the general formula for the nth term of the sequence is
`7+9(n-1)=7+9n-9=-2+9n`.

The sequence has 7 terms, so the sigma notation is:

`\sum^(7)_(n=1) (-2+9n)`