Hi I was wondering if someone could help me with this limit problem:

Find the lim x->a-, lim x->a+ and lim x->a

for the f(x)=(x^2-16)/(squareroot(x^2-8x+16)) a=4

I've tried to simplify the problem but after that i dont know wut to do =(

This is wut I've done:

y=(x^2-16)/(squareroot(x-4)^2)

y=(x^2-16)/abs(x-4)

any help would be appreciated.