document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=474400>Question 474400</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need help, here is the question, what is the answer, please, please please...\r<BR>\n" );
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document.write( "While traveling to and from a certain destination, you realized increasing your speed by 40 mph saved 4 hours on your return. If the total distance of the roundtrip was 640 miles, find the speed driven while returning. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #325460 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=325460\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> While traveling to and from a certain destination, you realized increasing your speed by 40 mph saved 4 hours on your return. If the total distance of the roundtrip was 640 miles, find the speed driven while returning. <BR>\n" );
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document.write( "let x=returning speed<BR>\n" );
document.write( "x-40=foward speed<BR>\n" );
document.write( "Travel time=distance/speed<BR>\n" );
document.write( "320/(x-40)-320/x=4<BR>\n" );
document.write( "LCD: x(x-40)<BR>\n" );
document.write( "320x-320(x-40)=4x(x-4)<BR>\n" );
document.write( "320x-320x+12800=4x^2-16x<BR>\n" );
document.write( "4x^2-16x-12800=0<BR>\n" );
document.write( "Use quadratic formula to solve<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "a=4, b=-16, c=-12800<BR>\n" );
document.write( "x=[-(-16)ħsqrt((-16)^2-4*4*-12800)]/2*4<BR>\n" );
document.write( "x=[16ħsqrt(205056)]8<BR>\n" );
document.write( "x=(16ħ452.83)/8<BR>\n" );
document.write( "x=58.60<BR>\n" );
document.write( "or<BR>\n" );
document.write( "x=-54.60 (reject, x>0)<BR>\n" );
document.write( "ans:<BR>\n" );
document.write( "Returning speed=58.60 mph </SPAN>\n" );
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