

I Don't Understand How Someone Would Ever Think to Do This
EDIT: I was fully aware that the lines are the same line when I was trying to solve the problem.
Hello! I was practicing for the Algebra portion of the SAT and stumbled upon this delightfully rage inducing question. The rationale given doesn't quite make sense to me. I don't see how anyone would think to solve for x first, especially when we usually want to put y in front (because of y = mx + b). Does anybody who has gotten a problem similar to this have any idea of how to approach this kind of thing in the future?