The Path of Flight (Trajectory) of a Football Thrown by a Quarterback

Short Answer

The path of flight (trajectory) of a football thrown by a quarterback is described by the following function: $\quad y ( x ) = - 0.002 x ^ { 2 } + 0.7 x + 7$
where $y =$ vertical position of football relative to the ground $( \mathrm { m } )$
$x =$ horizontal position of football relative to launch position (m)
How high above the ground is the football when it is 30 yards downfield from the quarterback?
a. $17.05 \mathrm {~m}$
b. $17.5 \mathrm {~m}$
c. $8.95 \mathrm {~m}$
d. $34.1 \mathrm {~m}$