Answer:
y = (9/2)x
Explanation:
Since the relation is proportional, the equation is ...
y = kx
For any (x, y) pair, you can find k as ...
y/x = k
Using the first pair, we get ...
k = 9/2
so the equation is ...
y = (9/2)x
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In decimal, that's ...
y = 4.5x