document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=981452>Question 981452</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a dolphin show, the height h in feet reached by a dolphin t seconds after breaking the surface water is given by h=-4t^2 - 20t.Find how many seconds after breaking the surface water will the dolphin reach 25 feet to get the fish from the trainer's hand? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #602411 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=602411\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> h=25=-4t^2-20t;I think this has to be -4t^2+20t, because otherwise as t increases from zero, the height gets less and less.\r<BR>\n" );
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document.write( "4t^2-20t+25=0; if I move everything to the left side.\r<BR>\n" );
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document.write( "(2t-5)^2=0<BR>\n" );
document.write( "2t=5<BR>\n" );
document.write( "t=2.5 seconds.  NOTE: if I use the equation given with -20t, I get t=-2.5 seconds\r<BR>\n" );
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document.write( "-4(2.5)^2+20(2.5)=-25+50=25\r<BR>\n" );
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document.write( "2.5 seconds<BR>\n" );
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