Question 738681
<font face="Times New Roman" size="+2">


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ D\ =\ 0.054x^2\ +\ 0.058x]


If you want to be able to stop in 65 feet, the question becomes "what *[tex \LARGE x] value do I need so that *[tex \LARGE D\ =\ 65].


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 0.054x^2\ +\ 0.058x\ =\ 65]


which is to say:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 0.054x^2\ +\ 0.058x\ -\ 65\ =\ 0]


Just solve the quadratic using the quadratic formula.  Of course, you must discard the negative root.  Negative speed in this context is absurd.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
<font face="Math1" size="+2">Egw to Beta kai to Sigma</font>
My calculator said it, I believe it, that settles it
<div style="text-align:center"><a href="http://outcampaign.org/" target="_blank"><img src="http://cdn.cloudfiles.mosso.com/c116811/scarlet_A.png" border="0" alt="The Out Campaign: Scarlet Letter of Atheism" width="143" height="122" /></a></div>
</font>