For an equation to be proportional, it must have no y intercept, and it must have a slope. So,
y=4x+4 This equation isn't proportional because it has a y-intercept (+4)
y=4x+2 This equation isn't proportional because it has a y-intercept (+2)
y=4x This equation is proportional because it has no y-intercept, and a slope.
