A t-shirt is fired straight up from a t-shirt cannon at ground level. After t seconds, its height ab ove the ground is h meters, where h=-16t^(2)+48t. how long the t-shirt was at least 27 meters above the ground.
Substitute in 27 for h in the equation
27 = -16t^2 + 48t use quadratic formula to find TWO values of t one is the the shirt going up....the other is the shirt coming down
the time the shirt is at least 27 m above the ground is the difference of these two times.....