Question

Do all graphs of proportional relationships include the point (0, 0)? Explain.

Answer 1

No. For example, if I gave you the equation y= 3x+5, the y-intercept will be at (0,5), eliminating the (0,0).

Answer 2

Yes, because if the value of either quantity in a proportional relationship is 0, the value of the second quantity must also be 0. This can be found by substituting x = 0 or y = 0 into the equation that represents the relationship.