document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=886144>Question 886144</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A ball is propelled upward from ground level. After 1 seconds, its height in feet is a function defined by f(t)=-16t^2+64t. After how many seconds will it reach a height of 64 feet? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #535723 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=535723\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A ball is propelled upward from ground level. After 1 seconds, its height in feet is a function defined by f(t)=-16t^2+64t. After how many seconds will it reach a height of 64 feet?<BR>\n" );
document.write( "set f(t) to 64 and solve for t:<BR>\n" );
document.write( "f(t)=-16t^2+64t<BR>\n" );
document.write( "64=-16t^2+64t<BR>\n" );
document.write( "16t^2+64=64t<BR>\n" );
document.write( "16t^2-64t+64=0<BR>\n" );
document.write( "dividing both sides by 16 we get:<BR>\n" );
document.write( "t^2-4t+4=0<BR>\n" );
document.write( "(t-2)(t-2) = 0<BR>\n" );
document.write( "t = 2 seconds<BR>\n" );
document.write( " </SPAN>\n" );
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