document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=135567>Question 135567</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Use the given root to find the solution set of the polynomial equation.\r<BR>\n" );
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document.write( "x^4 - 21x^2 - 100 = 0\r<BR>\n" );
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document.write( "Root = 2i </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #99327 by </B><A HREF=/tutors/aboutme.mpl?userid=edjones><B>edjones(8007)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=edjones><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=edjones><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=99327\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x^4 - 21x^2 - 100 = 0<BR>\n" );
document.write( "This is a quadratic equation.<BR>\n" );
document.write( "Since one root is 2i one of the others is -2i<BR>\n" );
document.write( "(x-2i)(x+2i)=x^2+4<BR>\n" );
document.write( "(x^4-21x^2-100)/(x^2+4)<BR>\n" );
document.write( "=x^2-25 Long division.<BR>\n" );
document.write( "=(x-5)(x+5) Factoring.<BR>\n" );
document.write( "x=5, x=-5 <BR>\n" );
document.write( "5, -5 The other two roots.<BR>\n" );
document.write( " </SPAN>\n" );
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