document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=598399>Question 598399</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Corbin was driving his car at a speed of r miles per hour, when he had to stop suddenly. It took the car 254 feet to stop. The formula relating the distance d in feet required to stop to the speed r in miles per hour is d=0.05r(squared)+r. To the nearest mile per hour, how fast was Corbin traveling just before he braked? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #378631 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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/cgi-bin/show-face.mpl?user=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=378631\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Corbin was driving his car at a speed of r miles per hour, when he had to stop suddenly.<BR>\n" );
document.write( " It took the car 254 feet to stop.<BR>\n" );
document.write( " The formula relating the distance d in feet required to stop to the speed r in miles per hour is d=0.05r(squared)+r.<BR>\n" );
document.write( " To the nearest mile per hour, how fast was Corbin traveling just before he braked?<BR>\n" );
document.write( ":<BR>\n" );
document.write( "d = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=.05r%5E2%2Br ALIGN=MIDDLE  ALT=\".05r%5E2%2Br\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "d = 254, find r<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=.05r%5E2%2Br ALIGN=MIDDLE  ALT=\".05r%5E2%2Br\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 254<BR>\n" );
document.write( "A quadratic equation:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=.05r%5E2+%2B+r+-+254 ALIGN=MIDDLE  ALT=\".05r%5E2+%2B+r+-+254\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 0<BR>\n" );
document.write( "Use the quadratic formula to find r<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( "In this problem; x=r; a=.05; b=1; c= -254<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+%28-1+%2B-+sqrt%281%5E2-4%2A.05%2A-254+%29%29%2F%282%2A.05%29+ ALIGN=MIDDLE  ALT=\"r+=+%28-1+%2B-+sqrt%281%5E2-4%2A.05%2A-254+%29%29%2F%282%2A.05%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Do the math and you should get a positive solution of:<BR>\n" );
document.write( "r ~ 62 mph </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );