What characteristic do all graphs of proportional relationships have in common?
A. They have a positive slope.
B. The graph must pass through the origin.
C. They have a negative slope.
D. They are a vertical line.

Question

What characteristic do all graphs of proportional relationships have in common?
	A.	They have a positive slope.
	B.	The graph must pass through the origin.
	C.	They have a negative slope.
	D.	They are a vertical line.

ybarrap · Answer

If x is proportional to y then
$$
y=ax
$$
Where $a$ is some constant of "proportionality." It can be negative or positive. But one thing to note is that the y-intercept is zero. What does this mean for this question?

ybarrap · Answer

This is what $y=ax$ means:
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