document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=156573>Question 156573</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0618803718/algebrahomeworkh></A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> The height h, in feet of a baseball above the ground t seconds after it is hit, is given by    h= -16t^2 + 50t +4.5<BR>\n" );
document.write( "Use this equation to determine the number of seconds, to the nearest tenth of a second, from the time the ball is hit until the ball hits the ground.<BR>\n" );
document.write( "Show all of your algebra work. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #115374 by </B><A HREF=/tutors/aboutme.mpl?userid=gonzo><B>gonzo(654)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=gonzo><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=115374\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> h = -16t^2 + 50t + 4.5<BR>\n" );
document.write( "when the ball hits the ground, h will be 0<BR>\n" );
document.write( "so solve the equation<BR>\n" );
document.write( "-16t^2 + 50t + 4.5 = 0<BR>\n" );
document.write( "solve using quadratic equation (-b +/- sqrt(b^2-4ac))/2a.\r<BR>\n" );
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document.write( "a = -16<BR>\n" );
document.write( "b = 50<BR>\n" );
document.write( "c = 4.5\r<BR>\n" );
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document.write( "use calculator and do not round until the end.\r<BR>\n" );
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document.write( "b^2 = 2500<BR>\n" );
document.write( "4ac = 4*(-16)*4.5 = (-288)<BR>\n" );
document.write( "b^2-4ac = 2500 - (-288) = 2788<BR>\n" );
document.write( "sqrt(b^2-4ac) = 52.80151513\r<BR>\n" );
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document.write( "formula then becomes (-50 +/- 52.80151513) / -32\r<BR>\n" );
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document.write( "t = 3.212547345 or t = .087547348\r<BR>\n" );
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document.write( "substituting in original equation for t = 3.212547345\r<BR>\n" );
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document.write( "(-16 * 10.32046046) + (50 * 3.212547345) + 4.5 = something very close to 0.\r<BR>\n" );
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document.write( "substituting in original equation for t = .087547345\r<BR>\n" );
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document.write( "(-16 * .007) + (50 * .087) + 4.5 = something very positive so this is not the answer.  \r<BR>\n" );
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document.write( "answer is t = 3.2 seconds rounded to the nearest tenth of a second. </SPAN>\n" );
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