For the first one, since the slope is 0 the line must be just a horizontal line that passes through the given point. The equation would be y=-4 because the y coordinate for the point is -4.
For the second problem, utilize y=mx+b, the parent equation for slope intercept form (m-slope, b-y intercept).
y=mx+b
-4=-1/3(5)+b
b=-2 1/3
equation: y=-1/3x - 2 1/3