document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=480188>Question 480188</A>: <I><SPAN STYLE=\"word-break: break-all;\">  <BR>\n" );
document.write( "  Give an example of a relation that is NOT a function and explain why it is not a function.\r<BR>\n" );
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document.write( "I do not understand how to do this...please help its algebra.\r<BR>\n" );
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document.write( "  \r<BR>\n" );
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document.write( "  \r<BR>\n" );
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document.write( "  \r<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 #328889 by </B><A HREF=/tutors/aboutme.mpl?userid=Edwin+McCravy><B>Edwin McCravy(20055)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Edwin+McCravy><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=Edwin+McCravy><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=328889\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The equation \r<BR>\n" );
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document.write( "x = y²\r<BR>\n" );
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document.write( "is not a function because both (1,1) and (1,-1) satisfy the<BR>\n" );
document.write( "equation, and a function by definition cannot have two <BR>\n" );
document.write( "different y-values for the same x value.\r<BR>\n" );
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document.write( "To make a graph of y² = x, make a table of values:\r<BR>\n" );
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document.write( " x | y<BR>\n" );
document.write( " 9 | 3<BR>\n" );
document.write( " 9 |-3<BR>\n" );
document.write( " 4 | 2<BR>\n" );
document.write( " 4 |-2<BR>\n" );
document.write( " 1 | 1<BR>\n" );
document.write( " 1 |-1<BR>\n" );
document.write( " 0 | 0\r<BR>\n" );
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document.write( "plot the points:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%2C+%0D%0Acircle%289%2C3%2C.1%29%2Ccircle%284%2C2%2C.1%29%2C%0D%0Acircle%289%2C-3%2C.1%29%2C%0D%0Acircle%284%2C-2%2C.1%29%2C%0D%0Acircle%281%2C1%2C.1%29%2C%0D%0Acircle%281%2C-1%2C.1%29%2C%0D%0Acircle%280%2C0%2C.1%29%2C%0D%0A+graph%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%29+%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Connect them:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%2C+%0D%0Acircle%289%2C3%2C.1%29%2Ccircle%284%2C2%2C.1%29%2C%0D%0Acircle%289%2C-3%2C.1%29%2C%0D%0Acircle%284%2C-2%2C.1%29%2C%0D%0Acircle%281%2C1%2C.1%29%2C%0D%0Acircle%281%2C-1%2C.1%29%2C%0D%0Acircle%280%2C0%2C.1%29%2C%0D%0A+graph%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%2Csqrt%28x%29%29%2C%0D%0A%0D%0Agraph%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%2C-sqrt%28x%29%29+%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Also notice that it does not pass the vertical line<BR>\n" );
document.write( "test.  Below I have drawn three vertical lines which<BR>\n" );
document.write( "intersect the curve twice.  This cannot happen if<BR>\n" );
document.write( "the graph is that of a function.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%2C+%0D%0Agreen%28line%282.7%2C-15%2C2.7%2C15%29%2C+line%285.3%2C-15%2C5.3%2C15%29%2Cline%288.4%2C15%2C8.4%2C-15%29%29%2C+%0D%0A+graph%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%2Csqrt%28x%29%29%2C%0D%0Acircle%289%2C3%2C.1%29%2Ccircle%284%2C2%2C.1%29%2C%0D%0Acircle%289%2C-3%2C.1%29%2C%0D%0Acircle%284%2C-2%2C.1%29%2C%0D%0Acircle%281%2C1%2C.1%29%2C%0D%0Acircle%281%2C-1%2C.1%29%2C%0D%0Acircle%280%2C0%2C.1%29%2C%0D%0A%0D%0A%0D%0Agraph%28400%2C1600%2F7%2C-2%2C12%2C-4%2C4%2C-sqrt%28x%29%29+%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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