Question

A falling object travels a distance given by the formula d=4t+16t^2, where t is measured in seconds and d is measured in feet how long will it take for the object to travel 72ft

Answer 1

Answer:

2 seconds.

Step-by-step explanation:

Given $d=4t+16t^{2}$ and d = 72 ft

We need to solve $72=4t+16t^{2}$

$4t+16t^{2}-72=0$

$4t^{2}+t-18=0$

$4t^{2}+9t-8t-18=0$

$t(4t+9)-2(4t+9)=0$

$(t-2)(4t+9)=0$

$t-2=0,4t+9=0$

$t=2,t=-\frac{9}{4}$

Since, time can not be negative, so the required time is t = 2 seconds.