The first one has no slope because it will be a straight vertical line going through the x-axis. The second one will also be a straight line, except it will be a horizontal line through the y-axis.
The slope for the first one would be: y2-y1/x2-x1, so replace those with the coordinates and you'll get: -3-1/-7-(-7) => -4/0 so I guess the slope is zero
the slope for the second one would be: -3-(-3)/5-(-4)=> 0/9 I think this one would be undefined. Check to make sure, though!