Answer:
For linear equations we use:
p=mx+b ------ (1)
Now we have the following coordinates:
(x1,p1)= (1000,280) and (x2, p2)=(5000,400)
First we need slope (m)
m= [tex](400-280)/(5000-1000)[/tex]
= [tex]120/4000=0.03[/tex]
Now we will plug the value of m in the first equation
[tex]280=0.03(1000)+b[/tex]
=> [tex]280=30+b[/tex]
=> b = 250
Now plug into p=mx+b using only m=0.03 and b=250
[tex]p=0.03x+250[/tex]
When the unit price is $440, we can plug in 440 in for p;
[tex]440=0.03x+250[/tex]
=> [tex]0.03x=440-250[/tex]
=> [tex]0.03x=190[/tex]
=> x = 6333 refrigerators
The lowest price at which a refrigerator will be marketed, we can find this by plugging x = 0 in p=mx+b.
[tex]p=0.03(0)+250[/tex]
=> p = $250