document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=555680>Question 555680</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Help, please? I've been having trouble with these problems for my homework.\r<BR>\n" );
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document.write( "Use factoring to find the zeros of the quadratic function.<BR>\n" );
document.write( "1) G(x)=x^2+5x <BR>\n" );
document.write( "2) F(x)=x^2-x-6<BR>\n" );
document.write( "3) f(x)=x^2+2x-120\r<BR>\n" );
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document.write( "An object is propelled vertically upward from the top of a 256-foot building. The quadratic function s(t)=-16t^2+176t+256 models the ball's height above the ground, s(t), in feet, t seconds after it was thrown. How many seconds does it take until the object finally hits the ground?\r<BR>\n" );
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document.write( "Any help really, I'd be tremendously grateful.\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #361901 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=361901\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Use factoring to find the zeros of the quadratic function.<BR>\n" );
document.write( "1) G(x)=x^2+5x <BR>\n" );
document.write( "2) F(x)=x^2-x-6<BR>\n" );
document.write( "3) f(x)=x^2+2x-120\r<BR>\n" );
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document.write( "An object is propelled vertically upward from the top of a 256-foot building. The quadratic function s(t)=-16t^2+176t+256 models the ball's height above the ground, s(t), in feet, t seconds after it was thrown. How many seconds does it take until the object finally hits the ground?<BR>\n" );
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document.write( "1) G(x) = x^2 + 5x<BR>\n" );
document.write( "Factor: x(x+5) = 0 -> x = 0, x = -5<BR>\n" );
document.write( "2) F(x) = x^2 - x - 6<BR>\n" );
document.write( "Factor: (x-3)(x+2) = 0 -> x = 3, x = -2<BR>\n" );
document.write( "3) f(x) = x^2 + 2x - 120<BR>\n" );
document.write( "Factor: (x-10)(x+12) = 0 -> x = 10, x = -12\r<BR>\n" );
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document.write( "At ground level s(t) = 0:<BR>\n" );
document.write( "0 = s(t) = -16t^2 + 176t + 256<BR>\n" );
document.write( "Dividing through by -16 gives t^2 - 11t - 16 = 0<BR>\n" );
document.write( "Solve using the quadratic formula:<BR>\n" );
document.write( "t = (11 +- sqrt(121 + 64))/2<BR>\n" );
document.write( "This gives t = -1.3, 12.3<BR>\n" );
document.write( "Obviously we need the positive solution, t = 12.3 s<BR>\n" );
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