90x^2+15x-30 (hope this helps)
All are relations except for relation 3
Every time the y-value decreases by 1, the x-value increases by 2, so the slope is -1/2 throughout the line.
A straight line can be drawn through all the points and the line passes through the point where x=0 and y=0. This best describes a graph of paired points that form a proportional relationship. You can tell this because the line passes directly through the origin (0,0). It also says that it is a straight line that passes through the points, so most likely the line will contain points that have a proportional relationship. Hope that helps :)
