Using logarithms property of log(x)+log(y)=log(xy)
so here, you can sum the equation to;

so you can simply say that;

and by multiplying (x+6)*(x-6)

and as you know also that;

is same as

so you can simply state it as;

And you can check your work by substituting with 10 instead of x in the original function.
Hope this helps!
Answer:
the 3rd one
Step-by-step explanation: