9514 1404 393
Answer:
y = -3x
Explanation:
Your solution will be in the form ...
y = (something)
In order to get the y-term by itself, you need to add the opposite of everything else*:
3x +y +(-3x) = 0 +(-3x)
y = -3x . . . . . simplify
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* Anything you do to one side of the equation must also be done to the other side. Here, we added -3x to both sides.