A biologist has been observing a tree’s height. $11$ months into the observation, the tree was $17.14$ feet tall. $19$ months into the observation, the tree was $18.26$ feet tall. Let $x$ be the number of months passed since the observations started, and let $y$ be the tree’s height at that time. Use a linear equation to model the tree’s height as the number of months pass.

1. This line’s slope-intercept equation is .
2. $30$ months after the observations started, the tree would be feet in height.
3. months after the observation started, the tree would be $23.3$ feet tall.