document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=182861>Question 182861</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find a value for k that will make 4x^2 + 6.4x + k a perfect square. Describe the procedure that you used which requires algebra [that is, not trial and error]. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #137282 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=137282\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 4x^2 + 6.4x + k<BR>\n" );
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document.write( "Looking at just the terms with 'x':<BR>\n" );
document.write( "4x^2 + 6.4x<BR>\n" );
document.write( "Factor out 4:<BR>\n" );
document.write( "4(x^2 + 1.8x)<BR>\n" );
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document.write( "Take 1/2 of 1.8 and square it, to get:<BR>\n" );
document.write( "((1/2)(1.8))^2 = .9^2 = 0.81<BR>\n" );
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document.write( "Adding it in:<BR>\n" );
document.write( "4(x^2 + 1.8x + 0.81)<BR>\n" );
document.write( "4x^2 + 6.4x + 3.24<BR>\n" );
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document.write( "So, k = 3.24<BR>\n" );
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document.write( "The process above is called \"completing the square\".  For additional info see:<BR>\n" );
document.write( "http://www.purplemath.com/modules/solvquad3.htm<BR>\n" );
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