document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=54185>Question 54185</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am not clear about functions, so I need help figuring this out. Could someone please help?<BR>\n" );
document.write( "Which of the following is not a function of x?<BR>\n" );
document.write( "y=x^2+5x+3<BR>\n" );
document.write( "y-3=6x<BR>\n" );
document.write( "6x= -y^2+3<BR>\n" );
document.write( "0=5x-y+1 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #36486 by </B><A HREF=/tutors/aboutme.mpl?userid=funmath><B>funmath(2933)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=funmath><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=36486\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The way that I attack these is to look at the exponents of the y's.  If y is raised to an even integer power, x is not a function of y.  <BR>\n" );
document.write( "Therefore, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6x=-y%5E2%2B3 ALIGN=MIDDLE  ALT=\"6x=-y%5E2%2B3\"   DISABLED_style= \"max-width:90%; height:auto;\" > is not a function of x because y is raised to the 2nd power and 2 is even.<BR>\n" );
document.write( "Graphically, even powers of y's are represented by ellipses, circles, sideways parabolas (which is what this one is) and certain types of hyperbolas that are not functions because they do not pass the vertical line test.<BR>\n" );
document.write( "Happy Calculating!!! </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );