# How do you simplify #81^(-3/2)#?

##### 2 Answers

Sep 19, 2016

#### Explanation:

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Sep 19, 2016

#### Explanation:

Recall: 2 laws of indices

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Note that 81 is both a square number and a 4th power.

However, the square root can be obtained immediately.

In work on indices, usually only the principal (+) square root is considered.