Answer:
G
Explanation:
a proportional relationship is defined by
y = ax
that means, if x = 0, then also y = 0.
let's look at the slope (the constant of change) :
y coordinate change / x coordinate change
when going from 1 point to another in the line.
we see e.g. for (4, 9) and (5, 12)
x changes by +1 (from 4 to 5).
y changes by +3 (from 9 to 12).
the slope is +3/+1 = 3.
but the slope cannot be the "constant of proportionality" ("a" above), because starting e.g. from (2, 3) to get to x = 0 would mean
x has to change by -2 (= -2×1).
and then y has to change by -6 (= -2×3) to keep the same slope "alive".
and so, for x = 0, we would get y = -3. but not 0.
the only equation with slope 3 (the factor of x, yes) is in G.
therefore, G is the right answer.
we can also check, when using x = 4, x = 5 and x = 2, we get the given y-values (9, 12, 3) from y = 3x - 3.
so, it is correct.