#### Answer

$y-8=0$

#### 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 $
\left(
-7,8
\right)$ and with a slope of $m=
0
$ (since the line is horizontal), is
\begin{array}{l}\require{cancel}
y-8=0(x-(-7))
\\\\
y-8=0(x+7)
\\\\
y-8=0
.\end{array}