SOLUTION: The distance traveled by an object moving in a straight line is given by s = t2 - 8t, where s is in feet and t is the time in seconds the object has been in motion. How long (to t

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Question 298733: The distance traveled by an object moving in a straight line is given by s = t2 - 8t, where s is in feet and t is the time in seconds the object has been in motion. How long (to the nearest tenth) will it take the object to move 9 feet?
Answer by nerdybill(7384) About Me  (Show Source):
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The distance traveled by an object moving in a straight line is given by s = t2 - 8t, where s is in feet and t is the time in seconds the object has been in motion. How long (to the nearest tenth) will it take the object to move 9 feet?
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The problem gives you the formula:
+s+=+t%5E2+-+8t
Simply substitute s for 9 and solve for t:
+9+=+t%5E2+-+8t
+0+=+t%5E2+-+8t+-+9
Factoring the right side:
+0+=+%28t%2B1%29%28t-9%29
t = {-1, 9}
We can toss out the negative solution leaving:
t = 9.0 secs