You didn't give the multiple choice so no one can help you do make sure to include that next time
The answer: $24.05
How to:
Go through the graph and add all the values together
Then subtract $3.00 from the cost
Then add 4% sales tax
To find the sales tax multiply the purchase price by the sales tax rate. Remember to convert the sales tax rate from a percent to a decimal number. Once the sales tax is calculated, it is added to the purchase price. The result is the total cost—this is what the customer pays.
The formula for slope is 
In this case:
so...
-1 <<<The slope
Hope this helped!
~Just a girl in love with Shawn Mendes
Convert to a decimal which would be 0.55 (11/20).
Then you want to multiply 0.55 by 100 (which is a whole number, all % is going to come from 100) to convert to a full % -> 0.55*100
Then you will simplify 0.55*100
You answer will be 55%.
