document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=121755>Question 121755</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The equation h=-16t^2 + 112t gives the height of an arrow, shot upward from the ground with an initial velocity of 112ft/s, where t is the time after the arrow leaves the ground .  Find the time it takes for the arrow to reach a height of 180 ft?\r<BR>\n" );
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document.write( "t = 180/112<BR>\n" );
document.write( "t = 1.6 seconds\r<BR>\n" );
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document.write( "Not sure if I'm doing the problem right but just double checking. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #89402 by </B><A HREF=/tutors/aboutme.mpl?userid=algebrapro18><B>algebrapro18(249)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=algebrapro18><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=89402\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Well that was a nice try but wrong.  What you need to do is solve the equation:<BR>\n" );
document.write( "180 = -16t^2+112t for t and see what you get.  \r<BR>\n" );
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document.write( "so solving we get:\r<BR>\n" );
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document.write( "180 = -16t^2+112t --> Subtract 180 from both sides<BR>\n" );
document.write( "0 = -16t^2+112t-180 --> factor out a 4 from the right hand side<BR>\n" );
document.write( "0 = 4(-4t^2+18t-45) --> divide both sides by 4<BR>\n" );
document.write( "0 = -4t^2+18t-45 --> factor<BR>\n" );
document.write( "0 = (-2t+5)(2t-9) --> set each factor equal to zero and solve\r<BR>\n" );
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document.write( "-2t + 5 = 0 --> subtract 5 from both sides<BR>\n" );
document.write( "-2t = -5 --> divide both sides by -2<BR>\n" );
document.write( "t = 5/2 or 2.5\r<BR>\n" );
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document.write( "2t - 9 = 0 --> Add 9 to both sides<BR>\n" );
document.write( "2t = 9 --> Divide both sides by 2<BR>\n" );
document.write( "t = 9/2 or 4.5\r<BR>\n" );
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document.write( "so the arrow will reach a hight of 180 feet at 2.5 seconds and 4.5 seconds. </SPAN>\n" );
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