Variable $x$ cannot be equal to any of the values $-3,3$ since division by zero is not defined. Multiply both sides of the equation by $\left(x-3\right)\left(x+3\right)$, the least common multiple of $x-3,x+3$.
Consider $\left(x-3\right)\left(x+3\right)$. Multiplication can be transformed into difference of squares using the rule: $\left(a-b\right)\left(a+b\right)=a^{2}-b^{2}$. Square $3$.
