document.write( "Question 468232: Gene's car traveled 210 miles averaging a certain speed. If the car had gone 5 mph faster, the trip would have taken 1 hour less. Find the average speed. \n" ); document.write( "

Algebra.Com's Answer #321280 by mananth(16946) $\"\"$ $\"About$

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speed x
\n" ); document.write( "speed x - 5
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\n" ); document.write( "Distance = same 210 miles
\n" ); document.write( "original time – time with increased speed =1
\n" ); document.write( "t=d/t
\n" ); document.write( "210/x-210/(x+5) =1
\n" ); document.write( "LCD= x (x+5)
\n" ); document.write( "multiply by LCD
\n" ); document.write( "210(x+5)-210x=1x(x+5)
\n" ); document.write( "210x+1050-210x=1x^2+5x
\n" ); document.write( "1050=1x^2+5x
\n" ); document.write( "x^2+5x-1050=0
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\n" ); document.write( "a= 1 b= 5 c= -1050
\n" ); document.write( "x1=(-5+sqrt(25-( -4200) ) / 2
\n" ); document.write( "= 4225
\n" ); document.write( "x1= 30
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\n" ); document.write( "x2=(5-sqrt(25-(-4200))/ 2
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\n" ); document.write( "x2= -35
\n" ); document.write( "Ignore negative value
\n" ); document.write( "speed of car = 30 mph
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