The limit as X approaches 8 of (2- cube root of x)/ (x-8)

lim (2-cbrt(x))/(x-8) as x->8

since as x->8, the denominator becomes zero, use l'hopital's rule:
lim (-1/3)(x^(-2/3))/1 as x->8
substitute.
(-1/3)(8^(-2/3))
(-1/3)(1/4)
-1/12