The height of the ball can be modeled by

…… (1)

Where the number of seconds after the ball is thrown

(a) Need to determine the -coordinate and -coordinate of the vertex of the graph of this quadratic model

The parabola equation has vertex at the point

Compare equation (1) with general equation, obtained and

So, t-coordinate of the vertex is

And, S-coordinate of the vertex is

Substitute, into

Thus, the -coordinate and -coordinate of the vertex of the graph are respectively