Answer
$y=-8$
Work Step by Step
Using $y-y_1=m(x-x_1)$ or the Point-Slope Form of linear equations, the equation of the line passing through $(
5,-8
)$ and with slope, $m=
0
,$ is
\begin{array}{l}\require{cancel}
y-(-8)=0(x-5)
\\\\
y+8=0
\\\\
y=-8
.\end{array}