A=$\frac{√x}{√x+3}$ + $\frac{2√x}{√x-3}$ - $\frac{3x+9}{(√x+3)(√x-3)}$
A = $\frac{√x(√x-3)+2√x(√x+3)-3x-9}{(√x+3)(√x-3)}$
A = $\frac{x-3√x+2x+6√x-3x-9}{(√x+3)(√x-3)}$
A = $\frac{3√x-9}{(√x+3)(√x-3)}$
A = $\frac{3(√x-3)}{(√x+3)(√x-3)}$
A = $\frac{3}{√x+3}$