document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=33642>Question 33642</A>: <I><SPAN STYLE=\"word-break: break-all;\">  Please help me solve this problem (2x2 matrix)<BR>\n" );
document.write( "If A=[1  -2, 1  0] and AB=[1  0, -1  2]Find B.\r<BR>\n" );
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document.write( "I tried multiplying A*AB changing the signs of AB but the answer did not come out right.  <BR>\n" );
document.write( "Answer should be B=[-1  0, -1  1]<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 #20044 by </B><A HREF=/tutors/aboutme.mpl?userid=Nate><B>Nate(3500)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Nate><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=20044\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let us use variables:<BR>\n" );
document.write( "B[a b, c d]<BR>\n" );
document.write( "A=[1 -2, 1 0]<BR>\n" );
document.write( "AB=[1 0, -1 2]<BR>\n" );
document.write( "A[1 -2, 1 0]*B[a b, c d]<BR>\n" );
document.write( "AB[a+b -2a, c+d -2c]=[1 0, -1 2]<BR>\n" );
document.write( "from this, we know that a=0 and c=-1<BR>\n" );
document.write( "AB[0+b 0, -1+d 2]=[1 0, -1 2]<BR>\n" );
document.write( "from this, we know that b=1 and d=0<BR>\n" );
document.write( "So..... B[0 1, -1 0]\r<BR>\n" );
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document.write( "I solved by using:<BR>\n" );
document.write( "A[a b, c d]<BR>\n" );
document.write( "is<BR>\n" );
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document.write( "I a , b I<BR>\n" );
document.write( "I c , d I\r<BR>\n" );
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