Find the domain and asymptote of the function f(x) = -3[ln(x^2-49)-ln(x+7)]

Thanks

I rewrite f(x) as follows, using properties of logarithms
f(x)= -3ln((x^2-49)/(x+7))
f(x)= -3ln((x+7)(x-7)/(x+7))
f(x)= -3ln(x+7)
The domain of f is
Dom{f(x)}=(7, oo) or Dom{f(x)}={x|x>7}
Finally f has a vertical asymptote at x=7