The general form of the equation of the line through the points
[tex](x_1,y_1)\text{ }(x_2,y_2)[/tex]is
[tex]y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]Here, take the points as
[tex](x_1,y_1)=(-3,-4),(x_2,y_2)=(5,-4)_{}[/tex]Substitute these values in the above formula:
[tex]\begin{gathered} y-(-4)=\frac{(-4-(-4))}{5-(-3)}\cdot(x-(-3)) \\ y+4=\frac{0}{8}\cdot(x+3) \\ y+4=0 \\ y=-4 \end{gathered}[/tex]So, the required line equation is
[tex]y=-4.[/tex]