Question

The function h(t)=-16t^2+16t+32 models the height of a ball t seconds after it was thrown in the air. How long does it take for the ball to hit the ground?

Answer 1

h(t)=-16(t²-t-2)=0 when the ball hits the ground.

So t²-t-2=(t-2)(t+1)=0, and t=2 or -1, but t=-1 is a time before the ball was thrown, so t=2 seconds is the answer.