Exercise 6 Page 327

Let's start by graphing the function y=870-14.8t, which is a linear function written in the slope-intercept form.

Here y is the height in feet of a hot-air balloon t minutes after it begins its descent. The y-intercept represents the initial height of 870 ft. The slope is the rate at which it descends, at 14.8 ft/min. This interpretation corresponds to Option B.