document.write( "Question 311465: Need to find the equations for x in this word problem. Thanks!
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\n" ); document.write( "Jim made a 450 mile trip in his car at a certain speed. If he ha
\n" ); document.write( "d gone 10 mph faster, he could have made the trip in one hour less time. Find his speed.
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Algebra.Com's Answer #222824 by ankor@dixie-net.com(22740)\"\" \"About 
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Jim made a 450 mile trip in his car at a certain speed.
\n" ); document.write( " If he had gone 10 mph faster, he could have made the trip in one hour less time.
\n" ); document.write( " Find his speed.
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\n" ); document.write( "Let s = that \"certain speed\"
\n" ); document.write( "then
\n" ); document.write( "(s+10) = the faster speed
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\n" ); document.write( "Write a time equation; time = dist/speed
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\n" ); document.write( "Actual time - faster time = 1 hr
\n" ); document.write( "\"450%2Fs\" - \"450%2F%28s%2B10%29\" = 1
\n" ); document.write( "multiply by s(s+10), results
\n" ); document.write( "450(s+10) - 450s = s(s+10)
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\n" ); document.write( "450s + 4500 - 450s = s^2 + 10s
\n" ); document.write( "Arrange as quadratic equation on the right
\n" ); document.write( "0 = s^2 + 10s - 4500
\n" ); document.write( "Use the quadratic formula to find s
\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "In this problem x=s, a=1, b=10 c=-4500
\n" ); document.write( "\"s+=+%28-10+%2B-+sqrt%2810%5E2-4%2A1%2A-4500+%29%29%2F%282%2A1%29+\"
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\n" ); document.write( "\"s+=+%28-10+%2B-+sqrt%28100+%2B+18000+%29%29%2F%282%29+\"
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\n" ); document.write( "\"s+=+%28-10+%2B-+sqrt%2818100+%29%29%2F%282%29+\"
\n" ); document.write( "Two solutions, but we just want positive solution
\n" ); document.write( "\"s+=+%28-10+%2B+134.536%29%2F%282%29+\"
\n" ); document.write( "s = \"124.536%2F2\"
\n" ); document.write( "s = 62.27 mph his actual speed
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\n" ); document.write( "Check solution, find the time at each speed
\n" ); document.write( "450/62.27 = 7.2266 hrs
\n" ); document.write( "450/72.27 = 6.2266 hrs
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\n" ); document.write( "difference: 1 hrs \n" ); document.write( "
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