[tex]\bf \sqrt{72x^6y^7z}\qquad
\begin{cases}
72=2\cdot 2\cdot 2\cdot 3\cdot 3\\
\qquad 2^2\cdot 2\cdot 3^2\\
x^6=x^{3\cdot 2}\\
\qquad (x^3)^2\\
y^7=y^{2+2+2+1}\\
\qquad y^2\cdot y^2\cdot y^2\cdot y^1\\
\qquad (y^3)^2\cdot y
\end{cases}\\\\
-----------------------------\\\\
\sqrt[2]{2^2\cdot 2\cdot 3^2\cdot (x^3)^2\cdot (y^3)^2\cdot y\cdot z}\implies 2\cdot 3\cdot x^3\cdot y^3\sqrt{2yz}
\\\\\\
6x^3y^3\sqrt{2yz}[/tex]
