Answer
$\dfrac{3}{x-3}; x\ne -3, 3$
Work Step by Step
Factor the numerator and the denominator completely to obtain:
$=\dfrac{3(x+3)}{(x-3)(x+3)}$
Cancel the common factors to obtain:
$\require{cancel}
\\=\dfrac{3\cancel{(x+3)}}{(x-3)\cancel{(x+3)}}
\\=\dfrac{3}{x-3}; x\ne -3, 3$
($x$ cannot be $-3$ and $3$ because they will make the original expression undefined.)
