72 can be written as 8 x 9
72 = 8 x 9 = 2^2 x 2 x 3^2
Thus, the expression can be rewritten as
[tex]\begin{gathered} 3\sqrt[]{72}\text{ = 3}\sqrt[]{2^2\times2\times3^2}\text{ = 3 }\times3\times2\sqrt[]{2} \\ =\text{ }3\text{ }\times6\sqrt[]{2} \end{gathered}[/tex]
The factor tree is shown below
