Sophie buys x packages of graph paper for $2.55 each (tax included). She pays with a $20 bill. Write an algebraic expression to represent the amount of change the cashier should give back to Sophie.

x=$20/$2.55.

Step-by-step explanation:

if each package is $2.55 then and it cost $20 then you will have to divide the numbers wich will give u x

20 - 2.55x

Step-by-step explanation:

20 is the dollar bill Sophie bought the packages with,  x represents the number of packages bought and 2.55 is the price for each, so by subtracting 20 by the cost of the total packages results in the amount of change the cashier should give back to Sophie.

For example, if Sophie bought 3 packages of graph paper with a $20 bill the cashier should give back to Sophie $12.35.

20 - 2.55 (3)

20 - 7.65  

12.35

hope this helps!

the formula of a slope:

we have the points (-2, 7) and (2, 3). substitute: