document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=141525>Question 141525</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 1. Which of the following are functions?  Explain your reasoning for a, b, and c.  \r<BR>\n" );
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document.write( "a. f(x) = 2 if x>1  otherwise  f(x) = -1\r<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\r<BR>\n" );
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document.write( "c. f(x) = x/10\r<BR>\n" );
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document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #103128 by </B><A HREF=/tutors/aboutme.mpl?userid=solver91311><B>solver91311(24713)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=solver91311><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=solver91311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=103128\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If any value of x results in two or more values for f(x), then f is NOT a function.\r<BR>\n" );
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document.write( "Graphically, that means that if you can find a vertical line that intersects the graph of the relation in two or more points, the relation is not a function.\r<BR>\n" );
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document.write( "It doesn't matter if more than one value of x results in the same value for f(x) -- the relation is still a function\r<BR>\n" );
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document.write( "In sum, if each x maps to exactly one value of f(x), even if more than one x maps to a given f(x), you have a function.  If any x maps to more than one value of f(x), you don't have a function. </SPAN>\n" );
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