document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=279546>Question 279546</A>: <I><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+++%28w1%2Fw2%29+=+%28f2-f%29%2F%29%28f-f1%29..solve+for+f+++ ALIGN=MIDDLE  ALT=\"+++%28w1%2Fw2%29+=+%28f2-f%29%2F%29%28f-f1%29..solve+for+f+++\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #203212 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=203212\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> (w1/w2) = (f2-f)/(f-f1)..solve for f<BR>\n" );
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document.write( "Cross-multiply:<BR>\n" );
document.write( "w1(f-f1) - w2(f2-f) =0<BR>\n" );
document.write( "w1f -w1f1 - w2f2+w2f = 0<BR>\n" );
document.write( "(w1+w2)f = w1f1+w2f2<BR>\n" );
document.write( "f = (w1f1+w2f2)/(w1+w2)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
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