document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=209702>Question 209702</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Determine whetherthe equation represents y as a function of x.<BR>\n" );
document.write( "|y|=4-x </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #158542 by </B><A HREF=/tutors/aboutme.mpl?userid=RAY100><B>RAY100(1637)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=RAY100><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=158542\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Function  can be  defined  as  an  expression  that  has  exactly  one output  for  every  input,,  or  passes  the  vertical  line  test.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "for [y] = 4-x,,,a  T  box  might  look  like<BR>\n" );
document.write( ".<BR>\n" );
document.write( "input(x),,,,output(y)<BR>\n" );
document.write( ".<BR>\n" );
document.write( "0,,,,,,,,,,,+/- 4<BR>\n" );
document.write( ".<BR>\n" );
document.write( "2,,,,,,,,,,,+/- 2<BR>\n" );
document.write( ".<BR>\n" );
document.write( "4,,,,,,,,,,,+/- 0<BR>\n" );
document.write( ".<BR>\n" );
document.write( "-4,,,,,,,,,,+/- 8<BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "We  find  more  than  one  output  possible  for  single  input,,,,therefore  not  a  function.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "A quick  sketch  of  the  above  data, shows  that  it  also  fails  the  vertical  line  test,  therefore not  a  function.<BR>\n" );
document.write( ".<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );