document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=672122>Question 672122</A>: <I><SPAN STYLE=\"word-break: break-all;\"> f(x)=-x^2-4x\r<BR>\n" );
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document.write( "intervals f is increasing and decreasing. \r<BR>\n" );
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document.write( "Give the equation of the line that represents the axis of the parabola. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #417809 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=417809\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> f(x)=-x^2-4x<BR>\n" );
document.write( "intervals f is increasing and decreasing.<BR>\n" );
document.write( "Give the equation of the line that represents the axis of the parabola.<BR>\n" );
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document.write( "axis of parabola:<BR>\n" );
document.write( "x = -b/(2a)<BR>\n" );
document.write( "x = -(-4)/(2(-1))<BR>\n" );
document.write( "x = 4/(-2)<BR>\n" );
document.write( "x = -2 (axis of parabola)<BR>\n" );
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document.write( "Since the coefficient associated with the x^2 term is negative, it is a parabola that opens downwards.<BR>\n" );
document.write( "Therefore:<BR>\n" );
document.write( "f is increasing in the region:<BR>\n" );
document.write( "(-oo, -2)<BR>\n" );
document.write( "and<BR>\n" );
document.write( "f is decreasing in the region:<BR>\n" );
document.write( "(-2, +oo)<BR>\n" );
document.write( "where<BR>\n" );
document.write( "oo is for infinity<BR>\n" );
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