Two parallel lines are graphed on a coordinate plane. how many of the lines could represent proportional relationship? Explain.

It's not necessary that either one represents a proportional

relationship. But if either one does, then the other one doesn't.

They can't both represent such a relationship.

The graph of a proportional relationship must go through

the origin. If one of a pair of parallel lines goes through

the origin, then the other one doesn't. (If two parallel lines

both went through the origin, then they would both be the

same line.)