**Section 2.5**: 80

Also:

- Suppose $V$ is the volume of a cube with sides of length $x$, measured in inches. Suppose the cube is expanding so that at time $t = 2$, $x$ is $20$ inches and $x$ is growing at rate of $3$ inches per minute. At what rate is $V$ increasing at that time?
- Suppose $y = \sqrt{x}$ and $x = t^2 + 3$. Find $\left.\dfrac{dy}{dt}\right|_{t = 3}$.