document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=174588>Question 174588</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am very unsure when it comes to functions.  Can you please help me to understand what makes something a function?  Here is the question.\r<BR>\n" );
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document.write( "Which of the following are functions?  Explain why/why not.\r<BR>\n" );
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document.write( "A.  f(x)=2 if x>1 otherwise f(x)=-1<BR>\n" );
document.write( "B.  f(x)=5 if x>0 or f(x)=-5 if x<0 or f(x)=5 or -5 if x=0<BR>\n" );
document.write( "C.  f(x)=x/10\r<BR>\n" );
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document.write( "Any help I recieve would be greatly appreciated as I am so utterly confused. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #129610 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=129610\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A function is a set of ordered pairs with the following <BR>\n" );
document.write( "restriction: Each x value must have only one y value<BR>\n" );
document.write( "associated with it.<BR>\n" );
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document.write( "Which of the following are functions? Explain why/why not. <BR>\n" );
document.write( "A. f(x)=2 if x>1 otherwise f(x)=-1<BR>\n" );
document.write( "This is a function.  Choose any value of x and the corresponding<BR>\n" );
document.write( "y value will be 2 if x>1, or it will be -1 if x<=1<BR>\n" );
document.write( "But each x value will have only one corresponding y value.<BR>\n" );
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document.write( "B. f(x)=5 if x>0 or f(x)=-5 if x<0 or f(x)=5 or -5 if x=0<BR>\n" );
document.write( "Not a function because you have two points (0,5) and (0,-5)<BR>\n" );
document.write( "Notice that x=0 has two associated y values, so not a function.<BR>\n" );
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document.write( "C. f(x)=x/10<BR>\n" );
document.write( "This is a function; each x value has one y value associated with it.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. <BR>\n" );
document.write( " </SPAN>\n" );
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