Answer
a) $y=-15x+145$
b) see attached image
c) 8
Work Step by Step
a) You know they start off with 145 lbs of food on day 0. With every day that goes on, they have 15 lbs less food. Therefore, the y intercept is 145, and the slopes is -15.
b) Graph the equation on graph paper
c) go to 25 on the y axis in your graph and draw a horizontal line. You will find that it crosses $y=-15x+145$ at (8,25), so the x value is 8.
