I'd say centimeters, if that's what you're looking for. Maybe 1-2 cm.
N2+40-28=
Combine like terms
n2+40-28=n2+12
Factor out 2
n•2+12=2(n+6)
Therefore the answer is 2(n+6)
This looks like a simple arithmetic series. Each term is 7 greater than the previous term.
Therefore, the Nth term is 17 + 7N.
For example, the first term is 17 + 7*1 = 17 + 7 = 24.
The second term is 17 + 7*2 = 17 + 14 = 31
etc...
And the 500th term is 17 + 7 * 500 = 17 + 3500 = 3517