#### Answer

$\{-20,20\}$

#### Work Step by Step

Since $(
-20
)^2=
400
$ and $
20
^2=
400
$, the square roots of $
400
$ are $
\{-20,20\}
$.

Published by
Pearson

ISBN 10:
0-32184-874-8

ISBN 13:
978-0-32184-874-1

$\{-20,20\}$

Since $(
-20
)^2=
400
$ and $
20
^2=
400
$, the square roots of $
400
$ are $
\{-20,20\}
$.

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