The height (in meters) of a shot cannonball follows a trajectory given by h(t) = -4.9t^2 + 18t - 0.4 at time t (in seconds). As an improper fraction, for how long is the cannonball above a height of 6 meters?
-4.9t^2 + 18t - 0.4 > 6
-4.9t^2 + 18t - 6.4 > 0 use quadratic formula to find the two t values subtract the smaller from the larger