Limit Sqrt
1. **State the problem:** We want to evaluate the limit $$\lim_{x \to 25} \frac{\sqrt{x} - 5}{x - 25}$$.
2. **Recognize the indeterminate form:** Direct substitution gives $$\frac{\sqrt{25} - 5}{25 - 25} = \frac{5 - 5}{0} = \frac{0}{0}$$ which is indeterminate, so we must simplify.
3. **Rewrite the expression:** Multiply numerator and denominator by the conjugate of the numerator to simplify.
$$\frac{\sqrt{x} - 5}{x - 25} \times \frac{\sqrt{x} + 5}{\sqrt{x} + 5} = \frac{(\sqrt{x} - 5)(\sqrt{x} + 5)}{(x - 25)(\sqrt{x} + 5)}$$
4. **Simplify numerator:** Use difference of squares:
$$ (\sqrt{x})^2 - 5^2 = x - 25 $$
So the expression becomes:
$$ \frac{x - 25}{(x - 25)(\sqrt{x} + 5)} $$
5. **Cancel common factors:**
Since $$x \neq 25$$ near the limit, cancel $$x - 25$$:
$$ \frac{1}{\sqrt{x} + 5} $$
6. **Evaluate the limit:** Substitute $$x = 25$$:
$$ \frac{1}{\sqrt{25} + 5} = \frac{1}{5 + 5} = \frac{1}{10} $$
**Final answer:**
$$ \boxed{\frac{1}{10}} $$