Question

When Nicole left her house in the morning, her cell phone battery was partially charged. The charge remaining in Nicole's battery, as a percentage, can be modeled by the equation b = -9t + 72b=−9t+72, where tt is the number of hours since Nicole left her house. What is the slope of the equation, and what is its interpretation in the context of the problem?

Answer 1

The slope of the equation modeling Nicole's cell phone battery charge over time is -9, representing a 9% decrease per hour, and the y-intercept is 72%, indicating the initial charge.

Step-by-step explanation:

The question asks about the slope of the equation b = -9t + 72, which models the charge remaining in Nicole's cell phone battery as a percentage over time. The slope of this equation is -9, which indicates how the battery charge decreases over time. In the context of the problem, the slope of the equation represents the rate at which the phone's battery is discharging. Since the slope is negative, it tells us that the battery percentage is going down by 9% each hour. The initial charge when t = 0 is 72%, which is the y-intercept of the equation.