We can multiply the top equation by 1 and the bottom equation by a -3.

Note: There are tons of different ways to use elimination, but generally, the smaller the number you multiply, the better. In this case, you don't really need to multiply, but for the sake of going through each step, we'll use it for now.

When we multiply the top by 1 and the bottom by -3 we get

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these new equations. Now, we can cancel out the 6x and the -6x and even the 3y and -3y.

When you cancel out the left side, you get left with 0, and -9 on the right side. This is a false statement because 0 cannot equal -9, and this system has no solution.

When we have no solution, the fourth step is irrelevant. We don't need to plug in solution into the original equation because we have no solution!