8.07 Writing Quadratic Functions

Question

Dominique throws a softball from the outfield. After 1 second, the ball is 15 feet high. After 4 seconds, the ball reaches its maximum height of 42 feet. After 7 seconds, it returns to a height of 15 feet.

What is the equation of the quadratic function that models the height of the ball h(t) at time t?

 h(t) = −2(t − 4)² + 42

 h(t) = 2(t + 4)² + 42

 h(t) = −3(t − 4)² + 42

 h(t) = 3(t + 4)² + 42

Answer 1

it's a downward opening parabola, so the coefficient of the squared term <0

that eliminates half the options

3rd option is correct

h(t)= -3(t-4)^2 +42

h(1) = -3(1-4)^2 + 42 = -27+42 = 15 feet after 1 second

h(4) =-3(0) +42 = 42 feet after 4 seconds

h(7) =-3(7-4)^2 +42 = -27+42 = 15 feet after 7 seconds