Answer
$y=2$
Work Step by Step
$Given,$ $2y=\sqrt (5y+6)$
Squaring both sides,we get:
$4y^{2}=5y+6$
$4y^{2}-5y-6=0$
$(4y+3)(y-2)=0$
$y=2,y=\frac{-3}{4}$
We need to check by the putting the obtained solutions in
the original equation.
$y=2$
$L.H.S=2X2=4$
$R.H.S=\sqrt (5X2+6)=\sqrt 16=4$
$L.H.S=R.H.S$,hence it is a valid solution
$y=\frac{-3}{4}$
$L.H.S=2X\frac{-3}{4}=\frac{-3}{2}$
$R.H.S=\sqrt (5X\frac{-3}{4}+6)=\sqrt \frac{24-15}{4}=\sqrt\frac{9}{4}=\frac{3}{2}$
$L.H.S$ does not equal $R.H.S$,hence it is an extraneous solution.