document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=61179>Question 61179</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I would like some help in determining all of the real and imaginary zeros of x^4+3x^2-4.  \r<BR>\n" );
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document.write( "Thank you for your help<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 #42111 by </B><A HREF=/tutors/aboutme.mpl?userid=tutorcecilia><B>tutorcecilia(2152)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=tutorcecilia><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=tutorcecilia><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=42111\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x^4+3x^2-4 [factor]<BR>\n" );
document.write( "(x^2-1)(x^2+4) [re-factor the difference of two squares]<BR>\n" );
document.write( "(x+1)(x-1)(x^2+4) [set each factor equal to zero]<BR>\n" );
document.write( "x+1=0<BR>\n" );
document.write( "x=-1<BR>\n" );
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document.write( "x-1=0<BR>\n" );
document.write( "x=1<BR>\n" );
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document.write( "and<BR>\n" );
document.write( "x^2+4=0<BR>\n" );
document.write( "x^2=-4<BR>\n" );
document.write( "sqrt(x^2)=sqrt(4)<BR>\n" );
document.write( "x=4i (an imaginary number]<BR>\n" );
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document.write( "So, x=-1,1,-4i, or +4i\r<BR>\n" );
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