A rock is dropped from the top of a 2000-foot building. After second, the rock is traveling feet per second. After seconds, the rock is traveling feet per second. Let y be the rate of descent and x be the number of seconds since the rock was dropped. Part A: Write a linear equation that relates time x to rate y. (Hint: Use the ordered pairs (1,32) and (2,64) )
Part B: Use this equation to determine the rate of travel of the rock 17 seconds after it was dropped.

First locate the turning point (vertex) of the graph. which is at the coordinates x=5 and y=9 or (5; 9).to determine whether it's a maximum or mininum value, you have to discern whether the vertex's y-value is the highest value or lowest value the graph can reach. since the vertex's y-value, 9 is the highest value the graph can reach, it will be a maximum.another basic way to determine whether the vertex's value is max or min is to see if the graph is smiling or sad. if it's smiling, the turning point/vertex would be a minimum, while a sad parabola would have a maximum y-value at the vertex.