Linear & Exponential Growth Practice Test

A taxi charges a base fare plus a per-mile fee. The relationship between miles $x$ and total cost $y$ is $y=2.75x+4.50$. What does the slope represent, and what is the total cost for a 6-mile ride?​

A laboratory sample cools according to $T(t)=20+60(0.75)^t$, where $T$ is temperature in °C and $t$ is time in minutes. What does the 20 represent in context, and what is $T(2)$ to the nearest tenth?​