document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=271070>Question 271070</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Use factoring to solve the quadratic equation, check by substitution or by using a graphing utility and identifying x-intercepts.\r<BR>\n" );
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document.write( "x^2-x-72=0 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #198481 by </B><A HREF=/tutors/aboutme.mpl?userid=LarissaRichardson><B>LarissaRichardson(34)</B></A><img src=\"/images/stars/stars-07.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=LarissaRichardson><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=LarissaRichardson><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=198481\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x^2-x-72=0\r<BR>\n" );
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document.write( "Reverse Foil<BR>\n" );
document.write( "A.What multiplied together will give you x^2? <BR>\n" );
document.write( "Answer x times x<BR>\n" );
document.write( "B. What multiplied together will give you negative 72 and added will give you negative 1? <BR>\n" );
document.write( "Answer -9 times 8\r<BR>\n" );
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document.write( "Written as:<BR>\n" );
document.write( "(x-9)(x+8)<BR>\n" );
document.write( "And when you foil this you get your original problem of x^2-x-72\r<BR>\n" );
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document.write( "Now set both equal to zero\r<BR>\n" );
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document.write( "x-9=0<BR>\n" );
document.write( "x=0+9<BR>\n" );
document.write( "x=9\r<BR>\n" );
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document.write( "x+8=0<BR>\n" );
document.write( "x=0-8<BR>\n" );
document.write( "x=-8\r<BR>\n" );
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document.write( "Check both answers in original equation for correct answer.\r<BR>\n" );
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document.write( "9^2-9-72=0?<BR>\n" );
document.write( "81-9-72=0?<BR>\n" );
document.write( "72-72=0?Yes </SPAN>\n" );
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