At what time, t, does the object hit the ground? s(t)=t^2−4t−12 I don't understand as it = a variable, if it = 0 i could do it

Guest Feb 16, 2017

#1**+10 **

**At what time, t, does the object hit the ground? s(t)=t^2−4t−12**

\(\begin{array}{|rcll|} \hline s(t) =t^2-4t-12 &=& 0 \\ t^2-4t-12 &=& 0 \\ (t-6)(t+2) &=& 0 \\\\ t = 6 &\text{or}& t = -2 \quad (\text{no solution, because t < 0})\\ \hline \end{array} \)

At time **t = 6** the object does hit the ground.

heureka
Feb 17, 2017

#1**+10 **

Best Answer

**At what time, t, does the object hit the ground? s(t)=t^2−4t−12**

\(\begin{array}{|rcll|} \hline s(t) =t^2-4t-12 &=& 0 \\ t^2-4t-12 &=& 0 \\ (t-6)(t+2) &=& 0 \\\\ t = 6 &\text{or}& t = -2 \quad (\text{no solution, because t < 0})\\ \hline \end{array} \)

At time **t = 6** the object does hit the ground.

heureka
Feb 17, 2017