How do you get an answer?

Question

A base i thrown straight up from a rooftop 448 feet high. The fraction h(t)=-16t^2+48t+448 describes the ball's height above the ground,h(t), in feet, t seconds after it is thrown. How long will it take for the ball to hit the ground?

Answer 1

The ball hits the ground when h(t) =  0

0 = -16t² + 48t + 448

0 = t² - 3t - 28)              divide both sides by GCF, -16

0 = (t - 4)(t + 7)            FOIL

 

-7 is rejected

 

The ball hits the ground after 4 seconds.