Respuesta :

In this case, we'll have to carry out several steps to find the solution.

Step 01:

Data:

[tex]21\sqrt[3]{15}-9\sqrt[3]{15}[/tex]

Step 02:

radical functions:

[tex]21\sqrt[3]{15}-9\sqrt[3]{15}=12\sqrt[3]{15}[/tex]

The answer is:

[tex]12\sqrt[3]{15}[/tex]