document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=83031>Question 83031</A>: <I><SPAN STYLE=\"word-break: break-all;\"> EVALUATE THE DETERMINANT OF THE MATRIX <BR>\n" );
document.write( "(6   2)          THE ANSWER I GOT WAS -18+-2=-20<BR>\n" );
document.write( "(-1 -3)             But the answer the teacher gave me was 18+2=-16 <BR>\n" );
document.write( "                    and I was wondering how is that not negative and could you please explain to me what exactly is a determinant. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #59608 by </B><A HREF=/tutors/aboutme.mpl?userid=bucky><B>bucky(2189)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=bucky><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=59608\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Your teacher made a simple mistake by dropping the minus sign on the 18, and you were also incorrect.<BR>\n" );
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document.write( "To evaluate the two-by-two determinant you multiply along the diagonals ... doing the diagonal<BR>\n" );
document.write( "that goes from the left top to the right bottom first, and then the diagonal that goes from<BR>\n" );
document.write( "the right top to the left bottom next.  Then you subtract the second product from the first <BR>\n" );
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document.write( "For your problem, the first diagonal multiplication is +6 times -3 and the resulting<BR>\n" );
document.write( "product is -18.  The second diagonal multiplication is +2 times -1 and that product is<BR>\n" );
document.write( "-2. <BR>\n" );
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document.write( "Then you subtract the first from the second:<BR>\n" );
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document.write( "-18 - (-2) = -18 + 2 = -16<BR>\n" );
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document.write( "Eventually when you learn to work determinants you will be able to use them to solve<BR>\n" );
document.write( "sets of equations. Determinants are a very useful tool.  Just hang in there and you will<BR>\n" );
document.write( "get around to how to use them pretty soon. Meanwhile, learn the rules that your teacher<BR>\n" );
document.write( "is presenting to you and practice them.<BR>\n" );
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document.write( "Good luck and cheers. Hope this helps you ... </SPAN>\n" );
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