The equation for a line can be represented by the formula y=mx+b. M is the slope or rate of change and b is the y intercept. Since the equation y=5/2 does not have an x in it the slope is 0 and you have a perfectly straight horizontal line. Since we are just left with 5/2 that is our y intercept.
In other words, no matter what value you plug in for x, y will always be 5/2.
Answer: not sure how helpful this is, but the second one is correct (if it's the one that's corresponding to the blue line). The pink line, however, is incorrect if it is corresponding to the first equation. The first equation must have a y-intercept of 1.