To find the equation of a horizontal line passing throuh (3, 6)
Note, the for a horizontal line, there is no change in y, only the x is changing. Therefore, the slope of a horizontal line is zero
For this question, slope, m=0
[tex]\begin{gathered} x_1=3,y_1=6 \\ \text{ Using the formula y-y}_1=m(x-x_1) \\ we\text{ have } \\ y-6=0(x-3) \\ y-6=0 \\ y=6 \\ \text{ The equation of the line is y = 6} \end{gathered}[/tex]