Question

The ball's height (in meters above the ground), xxx seconds after Antoine threw it, is modeled by: h(x)=-2x^2+4x+16 How many seconds after being thrown will the ball hit the ground? seconds

Answer 1

Answer:

Step-by-step explanation:

If we are given the quadratic model, we know that the height of anything on the ground is 0 meters, so that model becomes

$0=-2t^2+4t+16$ I changed your x's to t's since t is for time.

Now we need to factor that quadratic and solve for time:

$0=-2(t^2-2t-8)$

Since -2 definitely does not equal 0, then

$t^2-2t-8=0$

Factor that and find t values of 4 and -2.  Again, we know that time will never be negative, so

t = 4 seconds.