The graph shows the number of gallons in a waiting pool that is being drained using the points (1,160) and (3,80) as (

x₁, y₁) and (x₂, y₂) respectively.

To find the equation of the line passing through these points, we can use the slope-intercept form of a linear equation:

y = mx + b

where m represents the slope and b represents the y-intercept.

The slope of a line passing through two points (x₁, y₁) and (x₂, y₂) can be calculated using the formula:

m = (y₂ - y₁) / (x₂ - x₁)

Plugging in the given values, we have:

m = (80 - 160) / (3 - 1)
= -80 / 2
= -40

Now, we can substitute the slope (m) into the slope-intercept form and solve for the y-intercept (b) using one of the given points.

Using the point (1, 160):

160 = -40(1) + b

160 = -40 + b

b = 200

Therefore, the equation of the line is y = -40x + 200.