Answer:

And we can use the quadratic formula given by:

Where
. And replacing we got:

And after solve we got:

Since the time cannot be negative our final solution would be
Step-by-step explanation:
We have the following function given:

And we want to find how long after the ball is thrown will it strike the ground, so we want to find the value of t that makes the equation of h equal to 0

And we can rewrite the expression like this:

And we can use the quadratic formula given by:

Where
. And replacing we got:

And after solve we got:

Since the time cannot be negative our final solution would be