Question

PLEASEEE HELP THANK YOU!!

Answer 1

6i
`√(21)`

Explanation:

Note that
`√(-1)` = i

Using the rule of radicals

`√(a)` ×
`√(b)` ⇔
`√(ab)`

Simplifying the radical, that is

`√(-84)`

=
`√(4(21)(-1))`

=
`√(4)` ×
`√(21)` ×
`√(-1)`

= 2 ×
`√(21)` × i

= 2i
`√(21)`

Hence

3
`√(-84)`

= 3 × 2i
`√(21)`

= 6i
`√(21)`