Question

Is 9999 in the sequence n²+2n?​

Answer 1

No

Explanation:

To find out, all we need to do is plug in 9999 into the sequence.

`9999 = n^2 + 2n`

By completing the square, we get
`(n+1)^2 = 1001`. 1001 is not a perfect square, which means that 9999 is not in the sequence.

hope this helped! :)