Answer:
Part a) The rate is equal to [tex]-\frac{7}{2}\frac{gallons}{hour}[/tex]
Part b) [tex]y=-3.5x+17[/tex]
Step-by-step explanation:
step 1
Let
x-----> the number of hours
y----> the number of gallons left in the tank
we know that
For [tex]x=0, y=17\ gallons[/tex] -----> represent the y-intercept
For [tex]x=4\ hours, y=3\ gallons[/tex]
Find the rate (slope of the linear equation)
[tex]m=\frac{3-17}{4-0}[/tex]
[tex]m=-\frac{14}{4}[/tex]
simplify
[tex]m=-\frac{7}{2}\frac{gallons}{hours}[/tex]
step 2
Find the equation of the line
the equation of the line in slope intercept form is equal to
[tex]y=mx+b[/tex]
we have
[tex]m=-\frac{7}{2}=-3.5[/tex]
[tex]b=17[/tex]
substitute
[tex]y=-3.5x+17[/tex]