Answer
$\frac{3(3x+13)}{(x+4)(x+5)}; x \ne -4,-5;$
Work Step by Step
$\frac{3}{x+4} + \frac{6}{x+5} = \frac{3(x+5)+ 6(x+4)}{(x+4)(x+5)} ; x \ne -4,-5;$
$= \frac{3x+15+ 6x+24}{(x+4)(x+5)} ; x \ne -4,-5;$
$= \frac{9x+39}{(x+4)(x+5)} ; x \ne -4,-5;$
$=\frac{3(3x+13)}{(x+4)(x+5)}; x \ne -4,-5$
