Answer
$y=-4$
Work Step by Step
$5y+6=-18-y$ $\longrightarrow$addition property of equality
$5y+6-6+y=-18-y-6+y$ $\longrightarrow$combine like terms
$6y=-24$ $\longrightarrow$multiplication property of equality
$6y\div6=-24\div6$ $\longrightarrow$simplify
$y=-4$