For the following equation, a. Write the value or values of the variable that make a denominator zero. These are the restrictions on the variable b. Keeping the restrictions in mind solve the equation. 

\(\frac { 3 } { x + 2 } - \frac { 1 } { x - 2 } = \frac { 4 x } { x ^ { 2 } - 4 }\) 

a. Write the value or values of the variable that make a denominator zero. 

\(x = \square\) (Use a comma to separate answers as needed.)