Evaluate the limit: _x 4 sqrt(x) - 2sqrt(x) - 4

Substitute $x=4$ into the numerator:

$$\sqrt{4} - 2 = 2 - 2 = 0$$

Substitute $x=4$ into the denominator:

$$\sqrt{4} - 4 = 2 - 4 = -2$$

Since the denominator is not zero when $x=4$, we can directly substitute the value of $x$ into the expression to find the limit.

$$\lim_{x \to 4} \frac{\sqrt{x} - 2}{\sqrt{x} - 4} = \frac{0}{-2}$$ $$= 0$$

The final answer is 0.