0.
Slope: -9
9
9
9.5
-9
-9
9
-14
y = 9 is a horizontal line with slope 0. Slope = (y2 - y1)/(x2-x1), and y is constant so that numerator is always 0. The y-intercept is where the line crosses the y-axis when x=0. Since y is always 9 in this case, that is the y-intercept.
12.2
The equations will have the same slope as y = 5x+9 but a different y intercept