Chapter 2 - Functions, Equations, and Graphs - Mid-Chapter Quiz - Page 89: 15

$y=1$

Using $y-y_1=m(x-x_1)$ or the Point-Slope Form of linear equations, the equation of the line with the given conditions, \begin{align*} y_1=1 ,\\x_1=3 ,\\m=0 ,\end{align*} is \begin{align*} y-1&=0(x-3) \\ y-1&=0 \\ y&=1 \end{align*}