How do you simplify $21/sqrt7$ ?

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Answer 1 · 2016-02-28T16:06:51

$=color(blue)(3sqrt7$

$21/sqrt7$

Rationalising the denominator:

$21/sqrt7= (21 xx color(blue)(sqrt7))/(sqrt7 xx color(blue)(sqrt7$

$=(21sqrt7)/7$

$=(cancel21sqrt7)/cancel7$

$=color(blue)(3sqrt7$

How do you simplify 21/sqrt721/sqrt7?