PLSSS HELPP Which equation represents a proportional relationship?

1.Y=7x-3
2.Y=150x
3.Y=21/x
4.y=2x+1

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?

Iam not good at math i wish i could