Answer: Choice B
-2y+20
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Explanation:
Solve for x in the first equation. Subtract 2y from both sides.
x+2y = 20
x = 20-2y
x = -2y+20
Which we can plug into the second equation to get
2x-3y = -1
2(-2y+20)-3y = -1
At this point, we have one variable remaining which means we can isolate it.
