Answer:
(a) $ 67.1
(b) $98.60
(c) $ 1.26
Explanation:
Given equation is

where x is the temperature in °F and y is the heating cost in $
To find heating cost for a specific temperature just substitute the value of x (temperature) in the equation
Part (a)
For x = 25 we get
y = -1.26(25)+ 98.6 = $ 67.1
Part (b)
For x = 0 we get
y = -1.26(0) + 98.6 = 0 + 98.6 = $98.60
Part (c)
For a 1 degree increase in temperature, the predicted decrease is the slope of the line
Slope of line = coefficient of x = -1.26
So decrease in cost for 1 degree increase in temperature = $1.26