a rock is thrown from the top of a tall building. the distance, in feet, between the rock and the ground x seconds after it is thrown is given by f(x)=-16x62-4x+382 How long after the rock is thrown does it hit the ground
The first thing we are going to do in this case is to rewrite the function correctly. Â We have then: Â f (x) = - 16x ^ 2-4x + 382 Â The moment the rock hits the ground we have f (x) = 0 Â 0 = -16x ^ 2-4x + 382 Â We solve the polynomial looking for its roots which are: Â x1 = -5.012803699004288 Â x2 = 4.762803699004288 Â We ignore the negative root. The solution is: Â x = 4.76 Â Answer:Â Â it hits the ground 4.76 s after is thrown
