Answer
$v=7$
Work Step by Step
$Given,$ $\sqrt (7v-4)=\sqrt (5v+10) $
Squaring,we get:
$7v-4=5v+10$
$7v-4+4=5v+10+4$
$7v-5v=14$
$2v=14$
$v=14\div2=7$
We need to check by putting the obtained value in the original equation :
$L.H.S=\sqrt(7X7-4)=\sqrt (49-4)=\sqrt 45=\sqrt (5X7+10)=R.H.S$
Hence,$v=7$ is a valid solution