Brandon throws a ball across a field. The ball's height, in feet, is modeled by the function ƒ(t) = –1∕2t2 + 2t + 6, where t represents time in seconds. How long does it take the ball to hit the ground? Question 4 options: A) 2 seconds B) 4 seconds C) 8 seconds D) 6 seconds

Respuesta :

Answer:

D. 6 seconds.

Step-by-step explanation:

When the ball hits the ground f(t) = 0 , so:

-1/2t^2 + 2t + 6 = 0

Take out the -1/2:

-1/2(t^2 - 4t - 12) = 0

-1/2(t - 6)(t + 2) = 0

t = -2 , 6.  We ignore the negative zero.

So the answer is 6 seconds.

Answer:

6 seconds is right!

I got it right in class