A line can be determined with two points.
The y-intercept is where a graph intersects the y axis.
Let 2 points lie on the y axis. Those are the y-intercepts.
2 lines can only have 0 intersections, 1 intersection, or infinitely many intersections.
Thus, if a line intersects another line more than 2 times, both lines must be the same line.
Using that information to create a line, you would have the line x=0.
x=0 is a vertical line that intersects the y-axis infinitely many times since they are the same line.
However, x=0 is not a function.
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