Answer:-140 miles
Step-by-step explanation:
Hope this will help u..............
The toy rocket hits the ground when h(t) = 0.
So, h(t) = 0 = -9t^2 + 81.
Solving the equation,
-9t^2 = -81
Dividing by -9
t^2 = 9
Taking the square root.
t = 3
The answer is 3 seconds.
