There is no X in this equation(y=2). So we just need to draw a line that parallel to the X-axis. Then we can know what y=2 looks like.
For the question e we can let x=0 first and find a point. Then let y=0 and find a point. Draw a line at two points. Then we can know what y=2x-4 looks like.
X runs 4. Y runs 2.25-2.85=-0.6. So the slope is -0.6/4=-0.15. So this function is y=-0.15+2.85.