The extra data costs are $20.99 monthly but they're offering 20% off that. What will my monthly cost be with the 20% off?

Discounted price= $16.792

Step-by-step explanation:

Giving the following information:

The extra data costs are $20.99 monthly, but they're offering 20% off that.

To calculate the discounted price, we need to use the following formula:

Discounted price= normal price*(1 - discount rate)

Discounted price= 20.99*0.8

Discounted price= $16.792

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below:

step-by-step explanation: