document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1199217>Question 1199217</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve for x.\r<BR>\n" );
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document.write( "x^4 - 5x^2 -12 = 0\r<BR>\n" );
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document.write( "I can write x^4 like this: (x^2)^2.\r<BR>\n" );
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document.write( "Let u = x^2.\r<BR>\n" );
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document.write( "u^2 - 5u - 12 = 0\r<BR>\n" );
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document.write( "After using the quadratic formula, I got the following:\r<BR>\n" );
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document.write( "u = (5 + sqrt{73})/2 and (5 - sqrt{73})/2.\r<BR>\n" );
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document.write( "I back-substituted for u.\r<BR>\n" );
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document.write( "x^2 = (5 + sqrt{73})/2 and x^2 = (5 - sqrt{73})/2.\r<BR>\n" );
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document.write( "Taking the square root on both sides, I got:\r<BR>\n" );
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document.write( "x = [(5 + sqrt{73}/2)]^(1/2)\r<BR>\n" );
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document.write( "x = [(5 - sqrt{73}/2)]^(1/2)\r<BR>\n" );
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document.write( "The textbook Answer for x are -2, -1, 1, 2.\r<BR>\n" );
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document.write( "Why is my answer wrong? \r<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 #832976 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=832976\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "The work you did is fine.  But if the textbook answers are -2, -1, 1, and 2, then your original polynomial is not right.<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x%2B2%29%28x-2%29%28x%2B1%29%28x-1%29=%28x%5E2-1%29%28x%5E2-4%29=x%5E4-5x%5E2%2B4 ALIGN=MIDDLE  ALT=\"%28x%2B2%29%28x-2%29%28x%2B1%29%28x-1%29=%28x%5E2-1%29%28x%5E2-4%29=x%5E4-5x%5E2%2B4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "It looks as if you started with the wrong polynomial.<br><BR>\n" );
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