Answer
$y=1$ or, in general form, $y-1=0$
Work Step by Step
Through $(5,1);$ slope $0$
Use the point-slope form of the equation of a line, which is $y-y_{1}=m(x-x_{1})$, where $(x_{1},y_{1})$ is a point through which the line passes and $m$ is the slope.
Both $(x_{1},y_{1})$ and $m$ are given. Substitute them into the formula and simplify to obtain the equation of this line:
$y-y_{1}=m(x-x_{1})$
$y-1=(0)(x-5)$
$y-1=0$
$y=1$ or, in general form, $y-1=0$
