document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=53784>Question 53784</A>: <I><SPAN STYLE=\"word-break: break-all;\"> i've tried this questin but i don't get how to do it.\r<BR>\n" );
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document.write( "Michelle threw a ball vertically upwards, with its height h, in metres, after a time of t seconds, being given the formula:<BR>\n" );
document.write( "h=8t-t^2\r<BR>\n" );
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document.write( "Q. find after what time the ball is first at a height of 12m </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #36017 by </B><A HREF=/tutors/aboutme.mpl?userid=jenrobrody><B>jenrobrody(19)</B></A><img src=\"/images/stars/stars-06.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jenrobrody><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=36017\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let h=12 and solve for t:<BR>\n" );
document.write( "12=8t-t^2  set equal to zero(add -8t and t^2 to both sides)<BR>\n" );
document.write( "t^2-8t+12=0    can be factored:<BR>\n" );
document.write( "(t-6)(t-2)=0    zero product rule:<BR>\n" );
document.write( "t-6=0   and t-2=0<BR>\n" );
document.write( "t=6     and t=2<BR>\n" );
document.write( "The ball is at a height of 12 at times 2 seconds and 6 seconds.<BR>\n" );
document.write( "The first time it reaches a height of 12 is 2 seconds.<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "h=8(2)-2^2<BR>\n" );
document.write( "h=16-4=12 </SPAN>\n" );
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