Answer:
Step-by-step explanation:
=x^2-x-12
Answer:

Step-by-step explanation:
Given


Required
The explicit formula
First, calculate 
Set n=2; So:


Substitute -25 for 


Calculate the common difference (d)



So, the nth term is:


Open bracket

Collect like terms


<span>A polygon has an angle sum of 360°, and each angle measures 90°. Let's find our what is the polygon.
=> 360 degrees polygon with 90 degree measure for each angles.
=> 360 degrees / 90 degrees = 4
Therefore the polygon is a square.</span>