Write out the form of the partial fraction decomposition of the function:
$$Q = \int_{3}^{7} \frac{3 x }{x^2 +6 x + 9} dx$$
Determine the numerical values of the coefficients, $A$ and $B$, where $B \leq A$ and $$\frac{3 x }{x^2 +6 x + 9} = \frac{A}{denominator} + \frac{B}{denominator}$$
$A =$ $B =$