The credit remaining on a phone card (in dollars) is a linear function of the total calling time made with the card (in minutes). The remaining credit after 24 minutes of calls is $21.64, and the remaining credit after 35 minutes of calls is $20.10. What is the remaining credit after 45 minutes of calls?

The remaining credit after 45 minutes of calls is $18.70

Step-by-step explanation:

Here, we have a linear model to work with

Let us have the coordinates as follows;

(time calling time, credit remaining)

So we have two points as follows;

(24,21.64) and (35,20.10)

The slope will be;

(20.1-21.64)/(35-24) = -1.54/11 = -0.14

So the equation looks like;

y = -0.14x + c

To get the y-intercept, we simply substitute a point

Let us use (35,20.10)

20.10 = -0.14(35) + c

c = 20.10 + 4.9

c = 25

So the full equation is;

y = -0.14x + 25

So for 45 minutes, simply substitute 45 for x

We have this as:

y = -0.14(45) + 25

y = -6.3 + 25 = $18.70

you would need to know all the numbers that are on there

step-by-step explanation:

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.