document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=424393>Question 424393</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a ball is thrown, its height in feet h after t seconds is given: <BR>\n" );
document.write( "h=vt-16t^2<BR>\n" );
document.write( "v=initial upward velocity in feet per second.  if v=21 feet per second, find all values of t which h=6 feet. Do not round intermediate steps, round answer 2 decimals.  THANK YOU!!!!!\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #295869 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=295869\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a ball is thrown, its height in feet h after t seconds is given:<BR>\n" );
document.write( "h=vt-16t^2<BR>\n" );
document.write( "v=initial upward velocity in feet per second. if v=21 feet per second, find all values of t which h=6 feet. Do not round intermediate steps, round answer 2 decimals.\r<BR>\n" );
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document.write( "..\r<BR>\n" );
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document.write( "equation:<BR>\n" );
document.write( "6=21t-16t^2<BR>\n" );
document.write( "-16t^2+21t-6=0<BR>\n" );
document.write( "16t^2-21t+6=0<BR>\n" );
document.write( "solve by quadratic formula,<BR>\n" );
document.write( "a=16, b=-21, c=6\r<BR>\n" );
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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;\" >\r<BR>\n" );
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document.write( "t=(-(-21)+-sqrt(21^2-4*16*6))/2*16<BR>\n" );
document.write( " =(21+-sqrt(441-384))/32<BR>\n" );
document.write( " =(21+-sqrt(57))/32<BR>\n" );
document.write( " =(21+sqrt(57)/32 or (21-sqrt(57)/32<BR>\n" );
document.write( " =0.89 sec or 0.42 sec<BR>\n" );
document.write( "ans:<BR>\n" );
document.write( "The ball reaches a height of 6 feet after 0.42 sec on its way up and returns to a height of 6 feet after 0.89 sec on its way down.<BR>\n" );
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