Answer
$$0$$
Work Step by Step
Given $$\lim_{x\to 0}\frac{\sqrt{x^2+4}-2}{x}$$
Then
\begin{align*}
\lim_{x\to 0}\frac{\sqrt{x^2+4}-2}{x}&=\lim_{x\to 0}\frac{\sqrt{x^2+4}-2}{x}\frac{\sqrt{x^2+4}+2}{\sqrt{x^2+4}+2}\\
&=\lim_{x\to 0}\frac{x^2+4-2}{x\sqrt{x^2+4}+2} \\
&=\lim_{x\to 0}\frac{x}{ \sqrt{x^2+4}+2}\\
&=0
\end{align*}