Answer:
(3) [tex]21\sqrt{12}[/tex]
Step-by-step explanation:
We can simplify the radical expression by grouping like factors.
[tex]3\sqrt2\,(7\sqrt6)[/tex]
We can group the non-radical factors (3 and 7) as well as the radical factors (2 and 6):
[tex](3 \cdot 7)(\sqrt2 \cdot \sqrt6)[/tex]
Then, we can simplify each grouping:
[tex](21)(\sqrt{2\cdot 6})[/tex]
[tex]= \boxed{21\sqrt{12}}[/tex]
