Using linear functions, we have that:
a) The equation for the line is: [tex]y = -500x + 5500[/tex]
b) The prediction is of 2250 sales with a price of $6.50.
--------------------------
The equation of a line is given by:
[tex]y = mx + b[/tex]
In which
Item a:
In this problem:
[tex]m = \frac{1500 - 2500}{8 - 6} = -\frac{1000}{2} = -500[/tex]
Thus:
[tex]y = -500x + b[/tex]
Point (6,2500) means that when [tex]x = 6, y = 2500[/tex], which we use to find b.
[tex]y = -500x + b[/tex]
[tex]2500 = -500(6) + b[/tex]
[tex]b = 5500[/tex]
Thus
[tex]y = -500x + 5500[/tex]
Item b:
[tex]y = -500(6.5) + 5500 = 2250[/tex]
The prediction is of 2250 sales with a price of $6.50.
A similar problem is given at https://brainly.com/question/21010520