Mary H. answered • 02/27/18
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Nathon,
If two things both equal y, then they have to equal each other. 3x + 2 = -3x - 4. Solve that for x, then plug it back in to solve for y.
You are in reality substituting one equation for y into the other equation. It's just a little out of the ordinary to have it so obvious, and also so easy to see how adding the equations would work as well as substituting.
Let me know if you have any problem seeing this.
Mary
