Part A
The vertex of a parabola is the lowest or highest point. The vertex in this graph is (2,-1).
Part B
You need to find the rate of change between the points when x=2 and x=3. When x=2, y=-1, and when x=3, y=0.5. You can find the average rate of change between these points by putting the difference of y over the difference of x. 0.5--1=1.5 and 3-2=1. The average rate of change is 1.5/1, or just 1.5.
