A biologist has been observing a tree's height. 11 months into the observation, the tree was 19.26 feet tall. 18 months into the observation, the tree was 20.38 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. a. This line's slope-intercept equation is b. 30 months after the observations started, the tree would be feet in height. c. months after the observation started, the tree would be 26.62 feet tall