- Simplify: x^2+6x+8/x^2-2x-8 . Identify any excluded values

- Simplify :
x^2-36/x^2+6x * x^3+4x^2/x^2-4x-12

x^2+6x+8 = (x+2)(x+4)

x^2-2x-8 = (x+2)(x-4)

The other one is

(x-6)(x+6) * x^2(x+4)
--------------------------------
x(x+6) * (x-6)(x+2)

Now you should be able to cancel factors and figure any excluded values (where the denominator is zero)