Thank you for the opportunity to help you with your question!
Let the y be the number of liters in the tub. Let x be the number of minutes passed since draining started. The slope will be -5, as per every minute that passes, the tub will lose 5 liters of water. We also know that the x-intercept (or when the tub is completely empty) is 888 minutes. So the x intercept is (888, 0). Then, we can use the slope interecept form of the the line:
y - y1 = m(x-x1).
Where y1 and x1 represent (x1, y1) a point on the graph (we can use x-intercept here)
M represents the slope (already computed above).
We plug them in:
y - 0 = -5(x - 888)
y = -5x + 4440
Please let me know if you need any clarification. I'm always happy to answer your questions.
Sep 22nd, 2015
To graph it, we see the y-intercept is (0,4440) and the x-intercept is (888,0). Just draw a line connecting these two!