Question

time (hours)
describe the rate of change for this relationship.
the amount of fuel left
by
per hour.

Explanation:

Step1: Pick two points on line

Choose $(x_1,y_1)=(9,0)$ and $(x_2,y_2)=(0,18)$

Step2: Calculate rate of change

Use slope formula: $\text{Rate of change} = \frac{y_2 - y_1}{x_2 - x_1}$
$\text{Rate of change} = \frac{18 - 0}{0 - 9} = \frac{18}{-9} = -2$

Step3: Interpret the value

The negative sign means fuel decreases.

Answer:

The amount of fuel left decreases by 2 gallons per hour.