document.write( "Question 1074383: During the first part of a trip a man travels 140km at a certain speed. He travels 63km on the second part at a speed 7km slower. The total time of the trip is 3 hours. How fast did he travel the first part of the trip? \n" ); document.write( "
Algebra.Com's Answer #689050 by addingup(3677)\"\" \"About 
You can put this solution on YOUR website!
(140/x)+(63/(x-7)) = 3
\n" ); document.write( "The common denominator is x(x-7). Join both equations into one:
\n" ); document.write( "7(29x-140)/(x(x-7)) = 3
\n" ); document.write( "7(29x-140) = 3x(x-7)
\n" ); document.write( "203x-980 = 3x(x-7)
\n" ); document.write( "203x-980 = 3x^2-21x
\n" ); document.write( "-3x^2-21x+203x-980 = 0
\n" ); document.write( "-(x-70)(3x-14) = 0
\n" ); document.write( "(x-70)(3x-14) = 0
\n" ); document.write( "x-70 = 0 or 3x-14 = 0
\n" ); document.write( "x = 70 or x = 14/3
\n" ); document.write( "--------------------------------
\n" ); document.write( "Let's try the 70 first:
\n" ); document.write( "140/70 = 2
\n" ); document.write( "63/(70-7) = 1
\n" ); document.write( "2+1 = 3 hours This is the correct answer.
\n" ); document.write( ":
\n" ); document.write( "John\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );