A line equation can be written in slope-intercept form, and this form is
[tex]y=mx+b[/tex]
Where m represents the slope and b the y-intercept. The slope given in the text is 0, therefore, we have a horizontal line. Notice that since the slope is null, the equation is reducted to y = constant.
[tex]\begin{gathered} y=0\cdot x+b \\ y=b \end{gathered}[/tex]
Since it passes through (6, -8), our equation has a constant value for y, therefore
[tex]y=-8[/tex]
This is our answer.
