#### Answer

$n=4$

#### Work Step by Step

$Given,$ $\sqrt (n+5)=\sqrt (5n-11)$
Squaring,we get:
$n+5=5n-11$
$n+5+11=5n-11+11$
$n+16-n=5n-n$
$4n=16$
$s=16\div4=4$
We need to check by putting the obtained value in the original equation :
$L.H.S=\sqrt(4+5) =\sqrt 9=3=\sqrt (5X4-11)=\sqrt (20-11)=R.H.S$
Hence,$n=4$ is a valid solution