document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=121022>Question 121022</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me understand .<BR>\n" );
document.write( "The equation is : ( a^-1 + b^-1)^2 . I need to simplify it.  The answer is (b^2+2ab+a^2)/a^2*b^2. <BR>\n" );
document.write( "Can you explain why.  Why after using a common denominator , the \" 2ab\"  is out of the fraction?<BR>\n" );
document.write( "Thank you . Viktor </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #88765 by </B><A HREF=/tutors/aboutme.mpl?userid=nabla><B>nabla(475)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nabla><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=88765\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I presume you are able to get to this step: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2Fa%5E2+%2B+1%2Fb%5E2+%2B+2%2F%28a%2Ab%29 ALIGN=MIDDLE  ALT=\"1%2Fa%5E2+%2B+1%2Fb%5E2+%2B+2%2F%28a%2Ab%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now, what is the common denominator? <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5E2%2Ab%5E2 ALIGN=MIDDLE  ALT=\"a%5E2%2Ab%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "Multiply each term by what it is missing to form the common denominator:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2Fa%5E2%2A%28b%5E2%2Fb%5E2%29+%2B+1%2Fb%5E2%2A%28a%5E2%2Fa%5E2%29+%2B+2%2F%28a%2Ab%29%2A%28a%2Ab%2F%28a%2Ab%29%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
document.write( "\n" );
document.write( "As you can see, the numerator becomes <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b%5E2%2Ba%5E2%2B2a%2Ab ALIGN=MIDDLE  ALT=\"b%5E2%2Ba%5E2%2B2a%2Ab\"   DISABLED_style= \"max-width:90%; height:auto;\" >, and the denominator is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5E2%2Ab%5E2 ALIGN=MIDDLE  ALT=\"a%5E2%2Ab%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );