Question

Mr. Richardson is using a pump to drain the community pool. This function describes the depth of the pool, in feet, after x hours.

y = -0.6x + 4
What does the number 4 represent?

Answer 1

the depth of the pool, in feet, before Mr. Richardson started draining it

Explanation:

y = -0.5x + 4 is the in the slope-intercept form, whose general form is

y = mx + b, where m is the slope of the line and b is the y-intercept. The y-intercept is where the line intersects the x axis and in order to intercept the y-axis, x has to be 0.

Thus, when the y-intercept is 4, we know that x-value is automatically 4 and therefore Mr. Richardson's pool was already at a depth of 4 feet before the draining began.