tis a little ambiguous there.
the value of "y" is indeed directly proportional to the value of "x", as "x" increases, "y" increases as well by some factor.
now, one can say that as "x" reaches 0, "y" drops abruptly, and not linearly, and therefore, there is not proportionality at that point.
a line that is increasing from the left to the right like this one, doesn't have to cross the origin, it may well be above the origin or below it, and is perfectly suited for the proportional scenario, since we simply discard the values that do not apply, like to the left of the origin, and still be considered "directly proportional".
