Algebra practice question

Answer: 5

From the first equation x = 3 + 2y. Substituting: 12 + 9y = 30, so y = 2 and x = 7. Then x − y = 5.

Common wrong answers

If you answered 2

2 is y alone; compute x − y = 5.

If you answered 7

7 is x alone; subtract y = 2.

If you answered 9

9 is x + y; the question asks for the difference, 7 − 2 = 5.

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