Explanation:
A small toy rocket is launched from a 30-foot HIGH pad.
The height (h, in feet ) of the rocket ABOVE THE GROUND t seconds after taking off is given by the formula h=-3t^(2)-9t+30
Not sure you have the equation posted correctly, but set h = 0 and solve for t
0 = -3t^(2)-9t+30 Use quadratic Formula with a = -3 b = -9 c = 30
to find t = 2 seconds