Question

use the information given for the year 1995 and 2000, letting x=5 represent 1995, x=10 represent 2000, and y the number of post offices, to write an equation that models the data.

Graph (amount of post offices)- 1995 has 28,392, 2000 has 27,876

Answer 1

There are many ways to model a set of data, linear, exponential, square, sqaure-root.
With only two points anything goes!
If it is linear, then use
y=ax+b
If it is exponential, try
y=ab^x
If it is square, try
y=ax^2+bx+c (but you have to assume one of a, b or c)
and so on.
Find the unknown constants using the given data and you'll have it!