If 4x + 5y = 34 and 3x - 2y = 14 what is x - y?
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Correct answer: A
Explanation
4x + 5y = 34
3x − 2y = 14
Second equation × 5:
15x − 10y = 70
First equation × 2:
8x + 10y = 68
Adding the equations:
23x = 138
⇒ x = 6
Now,
3x − 2y = 14
18 − 2y = 14
2y = 4
y = 2
x − y = 6 − 2 = 4