Question 156686
f(x)=1/x^2-9


To find the domain, you would have to find [what x can be without making the denominator zero].  So set the denominator, x^2-9, equal to zero:


x^2-9=0


Now factor out the left side.


(x-3)(x+3)=0


Now take each expression separately and set them equal to zero and solve.


x-3=0
x=3


x+3=0
x=-3


So to make the denominator zero, x would have to be 3 or -3.  So to get the domain, "what x can be without making the denominator zero", you would say anything but these two values.  In other words:


x is not 3 or -3.


Do you follow?
I hope this helped!


-Alani