Question 217262
g(x)=(x-5)/(x^2-36) . Find the domain. I know its not (-inf,inf) 


Step 1.  We need to find out when g(x) does not exist or it becomes undefined.  In this case, the denominator cannot equal to zero.  So we need to find out when the denominator is equal to zero.


Step 2.  Let's look at the denominator given as


{{{x^2-36=x^2-6^2}}}


Step 3.  We recognize that this equation is a difference of squares so we can factor is as


{{{x^2-6^2=(x+6)(x-6)=0}}} 


and we set the function equal to zero.  A zero will occur when x=6 and x=-6.  


Step 4.  So the domain is everywhere except at x=6 and x=-6.  Use can inequalities to describe this as follows:  -6 <x <6,  x<-6,  and x>6.  


I hope the above steps were helpful. 


For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra or for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.


And good luck in your studies!


Respectfully,
Dr J