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  1. Fireworks for the annual Fourth of July show are launched straight up from a steel platform. The launch of the entire show is computer controlled. The height of a particular firework in meters above the ground is given by h = –4.9t2 + 49t + 11.27, where time, t, is in seconds. Homework Help ✎

    1. What is the height of the platform?

    2. What is the maximum height the firework reaches?

    3. How many seconds until it hits the ground?

Substitute t = 0 to find the height of the platform.

Use the Quadratic Formula to find the roots. Average them to find the line of symmetry.

You have now found the parameter h in the general equation y = a(xh)² + k.
The given equation has the same a value, −4.9.
Solve for k by substituting the point you found in part (a).

h(x) = -4.9(t − 5)² + 133.77

The factored form reveals the intercepts. Remember to include the a value in your factored equation.