It looks like you're asking to simplify the expression:

$\sqrt{4x^9}$

To simplify this, we can break it down into two parts:

1. Square root of 4: The square root of 4 is 2, because $\sqrt{4} = 2$.
2. Square root of $x^9$: To simplify the square root of $x^9$, recall that $\sqrt{x^9} = x^{9/2} = x^4 \cdot x^{1/2}$, because $x^{9/2} = x^4 \cdot \sqrt{x}$.

Thus, we can rewrite the expression as:

$\sqrt{4x^9} = 2x^4 \sqrt{x}$

So, the simplest radical form of $\sqrt{4x^9}$ is:

$2x^4 \sqrt{x}$

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Would you like further clarification or details on the steps? Here are some related questions:

1. How do we simplify square roots with variables raised to even powers?
2. What is the difference between simplifying square roots and cube roots?
3. How do you simplify square roots of terms like $9x^6$?
4. What is the process of rationalizing a denominator with square roots?
5. Can you simplify square roots of expressions like $\sqrt{16x^{12}}$?

Tip: Always try to break down terms into perfect squares when simplifying square roots, as this can make the process easier!