Answer
$$ y= \frac{1}{2}.$$
Work Step by Step
Since $ n=\langle 0,1,0 \rangle $ and $(x_{0},y_{0},z_{0})=(-5,\frac{1}{2},\frac{1}{2})$
then the equation of the plane in scalar form is
$ a(x-x_{0})+b(y-y_{0})+c(z-z_{0})=0$
That is, $$0(x-3)+(y-\frac{1}{2})+0(z-\frac{1}{2})=0$$
and simplifying it, we get
$$ y=\frac{1}{2}$$
Hence the equation is given by
$$ y= \frac{1}{2}.$$
