SOLUTION: If a stone is tossed from the top of a 350 meter building, the height of the building as a function of time is given by h(t)=-9.81t^2-10t+350, where t = seconds, height is meters.

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Question 408041: If a stone is tossed from the top of a 350 meter building, the height of the building as a function of time is given by h(t)=-9.81t^2-10t+350, where t = seconds, height is meters. How many seconds will it take the stone to hit the ground? Round to the nearest hundredth place, include units in the answer.
Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website!
h(t)=-9.81t^2-10t+350
.
set h(t) to zero and solve for t:
h(t)=-9.81t^2-10t+350
0=-9.81t^2-10t+350
applying the "quadratic formula" we get:
t = {-6.51, 5.49}
throw out the negative solution leaves you with
t = 5.49 seconds
.
Details of quadratic follows:

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=13820 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: -6.50808653456555, 5.48767837130024. Here's your graph: