Question

Simplify the radical expression by rationalizing the denominator
4/√21

Answer 1

`(4)/(√(21)) =(4√(21))/(√(21)√(21)) =(4√(21))/(21)`

Answer 2

I think

`(4)/(√(21))`

is about as simple as this is going to get. For some reason teachers like the radicals in the numerator, so we multiply top and bottom by
`√(21)` and get

`(4)/(√(21)) * (√(21))/(√(21)) = (4√(21))/(21)`

Answer:
`(4√(21))/(21)`