SOLUTION: The Function g is defined below g(x)=x^2-2x-3/x^2-81 Find all the values of x that are NOT in the domain of g if there is more than one value, separate them with commas.

Algebra ->  Functions -> SOLUTION: The Function g is defined below g(x)=x^2-2x-3/x^2-81 Find all the values of x that are NOT in the domain of g if there is more than one value, separate them with commas.      Log On


   

Question 1104211: The Function g is defined below
g(x)=x^2-2x-3/x^2-81
Find all the values of x that are NOT in the domain of g
if there is more than one value, separate them with commas.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Recall that dividing by zero is undefined, so it is not allowed.

Set the denominator equal to zero, factor and use the zero product property to find the x values that solve the equation

x^2 - 81 = 0
x^2 - 9^2 = 0
(x-9)(x+9) = 0
x-9 = 0 or x+9 = 0
x = 9 or x = -9

The two x values not in the domain are x = 9 and x = -9. These x values make the denominator x^2-81 equal to zero.