SOLUTION: The position of an object moing in a straight line is given by s=2t^2-3t, where s is in meters and t is the time in seconds the object has been in motion. how long (to the nearest

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: The position of an object moing in a straight line is given by s=2t^2-3t, where s is in meters and t is the time in seconds the object has been in motion. how long (to the nearest       Log On


   

Question 307569: The position of an object moing in a straight line is given by s=2t^2-3t, where s is in meters 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 19 meters?
i think my answer is 3.7 seconds.
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for t when s = 19:
s+=+2t%5E2-3t Substitute s = 19.
19+=+2t%5E2-3t Rearrange into standard quadratic equation form:
2t%5E2-3t-19+=+0 Solve using the quadratic formula:t+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a where a = 2, b = -3, and c = -19.
t+=+%28-%28-3%29%2B-sqrt%28%28-3%29%5E2-4%282%29%28-19%29%29%29%2F2%282%29
t+=+%283%2B-sqrt%289%2B152%29%29%2F4
t+=+%283%2B-sqrt%28161%29%29%2F4
t+=+3.9 or t+=+-2.4 Discard the negative solution as the time, t, should be a positive quantity.
highlight%28t+=+3.9%29seconds.