sqrt(90a^3b^8) in simplest radical form

$$\sqrt{90a^3b^8}\\\\
=\sqrt{90}\sqrt{a^3}\sqrt{b^8}\\\\
=\sqrt{9}\sqrt{10}\sqrt{a^2}\sqrt{a}\sqrt{b^8}\\\\
=3\sqrt{10}\;a\sqrt{a}\;b^4\\\\
=3ab^4\sqrt{10a}\\\\$$

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