document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=165497>Question 165497</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This is probably so basic but it's been a VERY long time and it just doesn't make sense to me. Please help! Thanks\r<BR>\n" );
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document.write( "1. Which of the following are functions?  The last two problems, i.e., b & c, are multi part relations consider all parts when determining whether or not these relations are functions.  Explain your reasoning for a, b, and c. \r<BR>\n" );
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document.write( "a. f(x) = x + 5\r<BR>\n" );
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document.write( "b. f(x) = 3 if x>2 otherwise f(x) = -2\r<BR>\n" );
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document.write( "c. f(x) = 7 if x>0  or  f(x) = -7 if x<0  or  f(x) = 7 or -7 if x = 0 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #121991 by </B><A HREF=/tutors/aboutme.mpl?userid=gonzo><B>gonzo(654)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=gonzo><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=121991\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> here's the definition of function.<BR>\n" );
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document.write( "A function is an equation (this is where most definitions use one of the words given above) if any x that can be plugged into the equation will yield exactly one y  out of the equation.<BR>\n" );
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document.write( "looking at each of your selections will help to determine if they are functions or not.<BR>\n" );
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document.write( "a. f(x) = x + 5<BR>\n" );
document.write( "i would say yes.<BR>\n" );
document.write( "for every value of x, there can only be one value of f(x).<BR>\n" );
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document.write( "b. f(x) = 3 if x>2 otherwise f(x) = -2<BR>\n" );
document.write( "i would say yes again.<BR>\n" );
document.write( "for every value of x, there can only be one value of f(x).<BR>\n" );
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document.write( "c. f(x) = 7 if x>0  or  f(x) = -7 if x<0  or  f(x) = 7 or -7 if x = 0<BR>\n" );
document.write( "i think no.<BR>\n" );
document.write( "it looks like at first glance, that this would not be a function since it looks like there can be more than one value of f(x) for a value of x.<BR>\n" );
document.write( "the first part says<BR>\n" );
document.write( "f(x) = 7 if x > 0.<BR>\n" );
document.write( "that's one value of f(x) for every value of x > 0.<BR>\n" );
document.write( "the second part says<BR>\n" );
document.write( "f(x) = -7 if x < 0.<BR>\n" );
document.write( "again ok.  that's one value of f(x) for every value of x < 0.<BR>\n" );
document.write( "the third part says<BR>\n" );
document.write( "f(x) = +/- 7 if x = 0.<BR>\n" );
document.write( "here's where it falls down.<BR>\n" );
document.write( "that's 2 values of f(x) when x = 0.<BR>\n" );
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document.write( "definition says a and b are function, c is not.<BR>\n" );
document.write( "check out paul's online notes for a review of the subject if you have time.<BR>\n" );
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document.write( "http://tutorial.math.lamar.edu/classes/alg/functiondefn.aspx#Fcns_Defn_Ex2<BR>\n" );
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