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A furniture rental company charges a fixed amount plus a fee based on the number of days for which the furniture is rented. The graph below shows the amount paid for a different number of days to rent the furniture: A graph titled Furniture Rentals plots the Number of Days on the x axis and the Amount in dollars on the y axis. A straight line joins the ordered pairs 0, 80 and 4, 240. What is the fixed amount charged? $20 $40 $60 $80

Respuesta :

The fixed amount is the amount charged for 0 days' rental. The ordered pair (0, 80) tells you it is $80.

Answer:

The fixed amount that is charged is:

                     $ 80

Step-by-step explanation:

We are given a straight line joins the ordered pairs (0,80) and (4,240).

We know that  the equation of a line passing through two points (a,b) and (c,d) is calculated by:

              [tex]y-b=\dfrac{d-b}{c-a}\times (x-a)[/tex]

Here we have:

       (a,b)=(0,80) and (c,d)=(4,240)

Hence, the equation of line is:

[tex]y-80=\dfrac{240-80}{4-0}\times (x-0)\\\\\\y-80=\dfrac{160}{4}\times x\\\\\\y-80=40x\\\\y=40x+80[/tex]

Hence, the fixed charge is the initial charge i.e. when the number of days i.e. x value is zero.

Hence, when x=0 we have:

          y=80

       Hence, the fixed charge is:  80