Answer:
x = 120, y = 160
Step-by-step explanation:
I like to use the elimination strategy in this type of problem.
You need to get one of the terms on the right side of the equation equal to and opposite another term on the right side of the other equation. For example, I'm going to make the y term of the first equation equal and opposite the y term of the second equation by multiplying the entire first equation by -1.5.
-1.5 * (x + y) = (280) * -1.5
2.5x + 1.5y = 540
The new equations are (only the first one changed):
-1.5x - 1.5y = -420
2.5x + 1.5y = 540
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x = 120
Then plug this back into one of the equations.
(120) + y = 280
y = 160
You can check by plugging these into the other equation to make sure they are correct.