The expression in the image is $\sqrt{8}$, which represents the square root of 8.

To simplify $\sqrt{8}$: $\sqrt{8} = \sqrt{4 \times 2} = \sqrt{4} \times \sqrt{2} = 2\sqrt{2}$

So, the simplified form of $\sqrt{8}$ is $2\sqrt{2}$.

Would you like further details or have any questions?

Here are five related questions to expand on this:

1. What is the approximate decimal value of $\sqrt{2}$?
2. How would you simplify the square root of a larger number, such as $\sqrt{72}$?
3. Can square roots of negative numbers be simplified?
4. How do you rationalize a denominator with a square root in it?
5. What are cube roots, and how do they differ from square roots?

Tip: When simplifying square roots, always try to find the largest perfect square factor of the number.