Beginning Algebra With Applications, Chapter 5, 5.4, Section 5.4, Problem 44

Determine the equation of the line through the points whose coordinates are $(-3,-4)$ and $(5,-4)$.

Using the Slope Formula with $(x_1, y_1) = (-3,-4)$ and $(x_2, y_2) = (5,-4)$

$\displaystyle m = \frac{-4-(-4)}{5-(-3)} = \frac{0}{8} = 0$

The slope of the line is .

Using the point slope formula with $\displaystyle m = 0$ and $(x_1, y_1) = (-3,-4)$


$\begin{equation} \begin{aligned} y - y_1 =& m(x - x_1) && \\ y-(-4) =& 0 [x-(-3)] && \text{Substitute } m = 0, (x_1, y_1) = (-3,-4) \\ y +4 =& 0 && \text{Simplify} \\ y =& -4 && \text{Write the slope-intercept form} \end{aligned} \end{equation}$