Answer
No solution
Work Step by Step
We are given: $-y=\sqrt y+6$
Square each side:
$(-y)^2=(\sqrt y+6)^2$
$y^2=y+6$
$y^2-y-6=0$
$(y-3)(y+2)=0$
$y-3=0$ or $y+2=0$
$y=3$ or $y=-2$
Check:
$-3=\sqrt -3+6$ or $-2=\sqrt (-2)+6$
$-3 \ne \sqrt 3$ or $-2\ne 2$
Therefore, the original equation has no solution.