document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=608098>Question 608098</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Greetings mathematic overlords,\r<BR>\n" );
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document.write( "My conundrum is as follows, I have this equation I am using to calculate a few values:\r<BR>\n" );
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document.write( " 2x-(x/10)^2=y,  from 0 to 100\r<BR>\n" );
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document.write( "Now this equation isn’t especially difficult and I get plenty of values out of it, such as when x=36 y=59.04, when x=20 y=26, when x=100 y=100, plotting a nice curve.\r<BR>\n" );
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document.write( "My issue now is that I need a way to somehow reverse this formula, so that when I know ‘y’ but not ‘x’ I can find ‘x’. I’ve spent a good hour now trying to come up with any tangible way to calculate ‘x’ by only knowing ‘y’ but it is simply beyond my abilities. \r<BR>\n" );
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document.write( "If it’s not too much trouble would you be able to help me find the formula to find ‘x’ from only ‘y’ so that all answers tie in with the equation 2x-(x/10)^2=y?<BR>\n" );
document.write( "If possible it would be a great help to me if you were able to explain just how to come to determine such a formula so that I can work it out for myself in the future for similar equations.\r<BR>\n" );
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document.write( "Thank you for your time.<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 #383055 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=383055\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 2x - x^2 / 100 = y\r<BR>\n" );
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document.write( "200x - x^2 = 100y ___ x^2 - 200x = -100y\r<BR>\n" );
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document.write( "completing the square ___ x^2 - 200x + 10000 = 10000 - 100y\r<BR>\n" );
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document.write( "(x - 100)^2 = 100(100-y)\r<BR>\n" );
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document.write( "taking square root ___ x - 100 = ± 10 &#8730;(100-y) ___ x = 100 ± 10 &#8730;(100-y)\r<BR>\n" );
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document.write( " </SPAN>\n" );
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