Answer: Therefore, the rocket will reach its maximum height at around 7.56 seconds after launch.
Step-by-step explanation: To find the time at which the rocket will reach its maximum height, we need to use the vertex formula:
x = -b/2a
where a, b, and c are the coefficients of the quadratic equation. In this case, a = -16, b = 242, and c = 84.
Substituting these values into the formula:
x = -242/(2*(-16))
x = -242/-32
x ≈ 7.56 seconds
Therefore, the rocket will reach its maximum height at around 7.56 seconds after launch.