Question

if a stone is tossed from the top of a 330 meter building, the height of the stone as a function of time is given by h(t)=-0.8t^2-10t+330, where t is in seconds, and height is in meters. After how many seconds will the stone hit the ground?

Answer 1

You must find where is :

-0.8t^2-10t+330=

In google type:

"quadratic equation online"

When you see list of results click on:

webgraphingcom/quadraticequation_quadraticformula.jsp

When page be open in rectacangle type:

-0.8t^2-10t+330=0

and click option solve it.

Solutions are t=(-55/2) and t=15

Time can't be negative so t=15

Proof:
h(t)=h(15)=-0.8*(15^2)-10*15+330=
-0.8*225-150+330=
-180-150+330=-330+330=0

Answer 2

You must find where is :

-0.8t^2-10t+330=0

Answer 3

319.36