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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
+18956
+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
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#1
+18956
+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

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