document.write( "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?\r
\n" ); document.write( "\n" ); document.write( "i think my answer is 3.7 seconds. \n" ); document.write( "

Algebra.Com's Answer #220037 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
Solve for t when s = 19:
\n" ); document.write( " $\"s+=+2t%5E2-3t\"$ Substitute s = 19.
\n" ); document.write( " $\"19+=+2t%5E2-3t\"$ Rearrange into standard quadratic equation form:
\n" ); document.write( " $\"2t%5E2-3t-19+=+0\"$ Solve using the quadratic formula: $\"t+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a\"$ where a = 2, b = -3, and c = -19.
\n" ); document.write( " $\"t+=+%28-%28-3%29%2B-sqrt%28%28-3%29%5E2-4%282%29%28-19%29%29%29%2F2%282%29\"$
\n" ); document.write( " $\"t+=+%283%2B-sqrt%289%2B152%29%29%2F4\"$
\n" ); document.write( " $\"t+=+%283%2B-sqrt%28161%29%29%2F4\"$
\n" ); document.write( " $\"t+=+3.9\"$ or $\"t+=+-2.4\"$ Discard the negative solution as the time, t, should be a positive quantity.
\n" ); document.write( " $\"highlight%28t+=+3.9%29\"$ seconds. \n" ); document.write( "

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