Answer:
The graph in the attached figure
see the explanation
Explanation:
Let
x----> the time in hours
y ----> liters of water remaining in the fish pond
we have

This is the equation of a line in slope intercept form

where
m is the slope or unit rate
b is the y-intercept or initial value
In this problem we have
The slope or unit rate is equal to
----> is negative because is a decreasing function
The y-intercept or initial value is

The graph in the attached figure
Remember that
The y-intercept is the value of y when the value of x is equal to zero
The y-intercept is the point (0,480)
That means----> The initial amount of liters of water in the fish pond was 480 liters before drainage began (for x=0 hours).
The x-intercept is the value of x when the value of y is equal to zero
The x-intercept is the point (8,0)
That means----> The time required to empty the fish pond is 8 hours (for y=0 liters)