Answer: 
Step-by-step explanation:
(a) Given
Sam charge $5 for each dog for a thirty minute walk
For an hour which is double the thirty minutes, it must be double of the same charge.

(b)Given
With $20, Christie sells 100 cups of lemonade with a quarter per cup charge
For 100 cup, she generate a revenue of

So, she earns
that is , her profit is 
Answer:
$7.7 million
Step-by-step explanation:
Given: $6.8 million profit made by company.
13% increase in profit every year.
Now, finding the company´s profit in the year of 2006.
As we know there is 13% increase in profit.
∴ Profit increase= 
Next adding company´s profit with increase in profit to get profit in the year 2006.
∴
≅ $7.7
The company´s profit in the year 2006 is $7.7 million.
It doesn’t represent a function, since in a function- the x values can’t repeat,
In (-13,4) and (-13,9) the x values are the same.
I dont really know the difference between them lol; also it's a little blurry
sorry