document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=870567>Question 870567</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Which value of k makes the following equation an identity: 16n to the 4th power - 9 = (4n + k)(4n - k)\r<BR>\n" );
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document.write( "a. k = 3 <BR>\n" );
document.write( "b. k = 9 <BR>\n" );
document.write( "c. k = 4 <BR>\n" );
document.write( "d. k = 5\r<BR>\n" );
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document.write( "I don't know how to figure this out because I don't understand what an identity is. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #524957 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=524957\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 16n^2-(k)^2=(4n+k)(4n-k)\r<BR>\n" );
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document.write( "16n^2-9 \r<BR>\n" );
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document.write( "(4n)^2-(3)^2\r<BR>\n" );
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document.write( "(4n+3)(4n-3)\r<BR>\n" );
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document.write( "compare the factors\r<BR>\n" );
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document.write( "so k=3 </SPAN>\n" );
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