document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=335690>Question 335690</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am looking at an example of a quadratic equation x^2 - 4x - 7 =0\r<BR>\n" );
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document.write( "using the quadratic formula I come up with 4 (+or-)(-4^2-4(1)(-7))/2  the instructor simplified this to x = 4(+or-)2(11^1/2)  I don't see where the number 11 came from or how the 2 was pulled out of the square can someone explain.  I will have a similar question to this according to the teacher in a quiz next week and I need to understand this.  Thank-you. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #240675 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=240675\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> quadratic equation <BR>\n" );
document.write( "x^2 - 4x - 7 =0 <BR>\n" );
document.write( "---------<BR>\n" );
document.write( "a = 1 ; b = -4 ; c = -7<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "x = [-b +- sqrt(b^2-4ac)]/(2a)<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "x = [4 +- sqrt(16-4*1*-7)]/(2*1)<BR>\n" );
document.write( "------<BR>\n" );
document.write( "x = [4 +- sqrt(16+28)]/2<BR>\n" );
document.write( "---<BR>\n" );
document.write( "x = [4 +- sqrt(44)]/2<BR>\n" );
document.write( "---<BR>\n" );
document.write( "x = [4 +- sqrt(4*11)]/2<BR>\n" );
document.write( "----\<BR>\n" );
document.write( "x = [4 +- 2*sqrt(11)]/2<BR>\n" );
document.write( "---<BR>\n" );
document.write( "x = [2 +- sqrt(11)]<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "x = 2+sqrt(11) or x = 2-sqrt(11)<BR>\n" );
document.write( "==================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );