document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=156686>Question 156686</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The problem is:  Evaluate and find the domain.  f(x)=1/x^2-9  for x=4,a-5\r<BR>\n" );
document.write( "\n" );
document.write( "I am able to evaluate and came up with f(4)=1/7 and f(4)=1/a^2-10a+16.  What I don't understand is how to find the domain.  I know my book says the answer is: x is not equal to 3, and x is not equal to -3.  I just don't know how the domain came to be this, I don't understand how to find the domain.  Please help.\r<BR>\n" );
document.write( "\n" );
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 #115506 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=115506\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Well notice how if <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=3 ALIGN=MIDDLE  ALT=\"x=3\"   DISABLED_style= \"max-width:90%; height:auto;\" >, then <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%283%29=1%2F%28%283%29%5E2-9%29=1%2F%289-9%29=1%2F0 ALIGN=MIDDLE  ALT=\"f%283%29=1%2F%28%283%29%5E2-9%29=1%2F%289-9%29=1%2F0\"   DISABLED_style= \"max-width:90%; height:auto;\" > which is <b>NOT</b> defined. Also, if <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=-3 ALIGN=MIDDLE  ALT=\"x=-3\"   DISABLED_style= \"max-width:90%; height:auto;\" >, then <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%283%29=1%2F%28%28-3%29%5E2-9%29=1%2F%289-9%29=1%2F0 ALIGN=MIDDLE  ALT=\"f%283%29=1%2F%28%28-3%29%5E2-9%29=1%2F%289-9%29=1%2F0\"   DISABLED_style= \"max-width:90%; height:auto;\" > which is also <b>NOT</b> defined. So that's why there are domain restrictions of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%3C%3E-3 ALIGN=MIDDLE  ALT=\"x%3C%3E-3\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%3C%3E3 ALIGN=MIDDLE  ALT=\"x%3C%3E3\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );