#### Answer

$x=3$

#### Work Step by Step

$Given,\sqrt (5x+10)=5$
Squaring,
$5x+10=25$
$5x+10-10=25-10$
$5x=15$
$x=3$
We need to check by putting the obtained solution in the original equation:
$L.H.S=\sqrt (5X3+10)=\sqrt 25=5$
$R.H.S=5$
$L.H.S=R.H.S$,hence it is a valid solution.