#### Answer

$n=14$

#### Work Step by Step

$a_n=2n^2+5$ when $a_n=397$
$397=2n^2+5$
$\implies 392=2n^2$
$\implies 196=n^2$
$\implies \sqrt{196}=n$
$\implies n=14$

Published by
Brooks Cole

ISBN 10:
0-53449-636-9

ISBN 13:
978-0-53449-636-4

$n=14$

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