document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=821684>Question 821684</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rocket is fired upward with an initial velocity of 168 ft/s. Using the formula h = rt-16t^2 determine when the rocket is 360 ft high and when does it crash. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #494325 by </B><A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><B>TimothyLamb(4379)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><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=TimothyLamb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=494325\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ---<BR>\n" );
document.write( "h(t) = -16t^2 + 168t<BR>\n" );
document.write( "---<BR>\n" );
document.write( "at 360 feet:<BR>\n" );
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document.write( "h(t) = 360 = -16t^2 + 168t<BR>\n" );
document.write( "-16t^2 + 168t - 360 = 0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the above quadratic equation is in standard form, with a=-16, b=168, and c=360<BR>\n" );
document.write( "---<BR>\n" );
document.write( "to solve the quadratic equation, by using the quadratic formula, copy and paste this:<BR>\n" );
document.write( "-16 168 -360<BR>\n" );
document.write( "into this solver: https://sooeet.com/math/quadratic-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the two real roots (i.e. the two x-intercepts), of the quadratic are:<BR>\n" );
document.write( "t= 3 sec<BR>\n" );
document.write( "t= 7.5 sec<BR>\n" );
document.write( "---<BR>\n" );
document.write( "answer 1:<BR>\n" );
document.write( "the rocket is at 360 ft of altitude at 3 seconds after launch, and then again at 7.5 seconds after launch<BR>\n" );
document.write( "---<BR>\n" );
document.write( "---<BR>\n" );
document.write( "---<BR>\n" );
document.write( "at 0 feet:<BR>\n" );
document.write( "---<BR>\n" );
document.write( "h(t) = 0 = -16t^2 + 168t<BR>\n" );
document.write( "-16t^2 + 168t = 0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the above quadratic equation is in standard form, with a=-16, b=168, and c=0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "to solve the quadratic equation, by using the quadratic formula, copy and paste this:<BR>\n" );
document.write( "-16 168 0<BR>\n" );
document.write( "into this solver: https://sooeet.com/math/quadratic-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the two real roots (i.e. the two x-intercepts), of the quadratic are:<BR>\n" );
document.write( "t= 0 sec<BR>\n" );
document.write( "t= 10.5 sec<BR>\n" );
document.write( "---<BR>\n" );
document.write( "answer 2:<BR>\n" );
document.write( "the rocket crashes to earth at 10.5 seconds after launch<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve and graph linear equations:<BR>\n" );
document.write( "https://sooeet.com/math/linear-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve quadratic equations, quadratic formula:<BR>\n" );
document.write( "https://sooeet.com/math/quadratic-formula-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve systems of linear equations up to 6-equations 6-variables:<BR>\n" );
document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );