The expression you provided is:

$4\sqrt{5} + 5\sqrt{4}$

Let's simplify step by step:

1. $\sqrt{5}$ remains as is since it's an irrational number.
2. $\sqrt{4} = 2$ since the square root of 4 is 2.

Now, substitute that back into the expression:

$4\sqrt{5} + 5 \times 2 = 4\sqrt{5} + 10$

Thus, the simplified form of the expression is:

$4\sqrt{5} + 10$

Would you like more details on any of the steps?

Related Questions:

1. How do you simplify other square root expressions?
2. What are irrational numbers, and why is $\sqrt{5}$ one of them?
3. How do you add or subtract terms involving square roots?
4. Can square roots of non-perfect squares be simplified further?
5. What is the difference between rational and irrational numbers?

Tip: When simplifying square root expressions, always look for perfect square factors to simplify them further.