document.write( "Question 42340: A car is driven 850 miles. If it had gone 5.0 miles per hour faster it would have made the trip in 2.0 hour less time. What was the speed? \n" ); document.write( "

Algebra.Com's Answer #27457 by josmiceli(19441) $\"\"$ $\"About$

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850 = r*t
\n" ); document.write( "r = 850/t
\n" ); document.write( "850 = (r+5)(t-2)
\n" ); document.write( "850 = rt + 5t - 2r - 10
\n" ); document.write( "850 = t*(850/t) + 5t - 2(850/t) - 10
\n" ); document.write( "850 = 850 + 5t - 1700/t -10
\n" ); document.write( "-850 = -850
\n" ); document.write( "0 = 5t - 1700/t -10
\n" ); document.write( "5t - 1700/t = 10
\n" ); document.write( "5t^2 -1700 = 10t
\n" ); document.write( "5t^2 - 10t - 1700 = 0
\n" ); document.write( "t^2 - 2t - 340 = 0
\n" ); document.write( "use quadratic formula to find t
\n" ); document.write( "then use 850 = rt to find r
\n" ); document.write( "at^2 + bt + c = 0
\n" ); document.write( " $\"t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$ \n" ); document.write( "

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