$\"\"$

The first restaurant can be modeled by $\"\"$ .

The second restaurant can be modeled by $\"\"$ .

Where t = 3 represents 2003.The function $\"\"$ represents the total sales of the two restaurants.

The third restaurant can be modeled by $\"\"$ .

$\"\"$

$\"\"$ $\"\"$

The third restaurant can be modeled by $\"\"$ .