document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1174857>Question 1174857</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Determine whether the equation defines y as a function of x.\r<BR>\n" );
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document.write( "x2 + y = 25\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #800336 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=800336\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> solve for y to get:<BR>\n" );
document.write( "y = 25 - x^2\r<BR>\n" );
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document.write( "the definition of a function is that, each and every value of y has one and only one value of x.\r<BR>\n" );
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document.write( "that applies to this equation.\r<BR>\n" );
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document.write( "you can pick any value of x and you will get one and only one value of y.\r<BR>\n" );
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document.write( "for example:\r<BR>\n" );
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document.write( "x = 5, y = 25 - 25 = 0\r<BR>\n" );
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document.write( "x = 6, y = 25 - 36 = -11.\r<BR>\n" );
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document.write( "if you graph the equation, you will see something like this:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" src = \"http://theo.x10hosting.com/2021/021102.jpg\" >\r<BR>\n" );
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document.write( "the vertical line test will pass only one value of y for each and every value of x.\r<BR>\n" );
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document.write( "this means there is one and only one value of y for each and every value of x.\r<BR>\n" );
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document.write( "for example, a vertical line at x = 3 intersects with only one value of y at y = 25 - 3^2 = = 25 - 9 = 16.\r<BR>\n" );
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document.write( "here is a definition of a function from the internet.\r<BR>\n" );
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document.write( "<a  rel=nofollow HREF= \"http://www.berkeleycitycollege.edu/wp/wjeh/files/2012/01/note_function.pdf\" target = \"_blank\">http://www.berkeleycitycollege.edu/wp/wjeh/files/2012/01/note_function.pdf</>\r<BR>\n" );
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