The expression in the image you've provided is a fourth root of 625, written as:

$4 \sqrt{625}$

To solve this, we need to find the fourth root of 625, which is the number that, when raised to the power of 4, equals 625.

Steps:

1. Express the problem as: $x^4 = 625$
2. Find the fourth root of 625: $\sqrt[4]{625} = 5$

Thus, the fourth root of 625 is 5.

If you need further clarification or have any questions, feel free to ask!

Here are some related questions for you:

1. What is the cube root of 625?
2. How do you calculate the square root of a number?
3. How can you calculate higher-order roots for other numbers?
4. What is the relationship between square roots and higher-order roots?
5. How would you handle solving roots of negative numbers?

Tip: To simplify radical expressions, try to express the number under the root as a product of powers of prime factors!