Question

Abigail tosses a coin off a bridge into the stream below. The distance, in feet, the coin above the water is modeled by the equation y=−16x2+96x+112 When does the coin hit the water?

Answer 1

Answer:

7 seconds

Step-by-step explanation:

Distance of the coin above the water is modeled by the equation

$y=-16x^2+96x+112$

where $x$ is time taken to cover the distance

Now equating with zero.

$0=-16x^2+96x+112\\\Rightarrow 16x^2-96x-112=0\\\Rightarrow x=\dfrac{-\left(-96\right)\pm \sqrt{\left(-96\right)^2-4\times \:16\left(-112\right)}}{2\times \:16}\\\Rightarrow x=7, -1$

So, time taken by the coin to hit the water is 7 seconds.