What is the simplest radical from of the square root of 84?

First note that 84=4x21 and 4 is a perfect square.

So square root of (84)=square root (4x21)=Square root (4) Square root (21)=

2 multiplied by the square root of 21.

You can also write this using rational exponents, but this is not in radical form.

It is an equivalent expression, however.

2 x (21)1/2