If x + y = 20 and x − y = 6, what is the value of x?

Correct answer: A. 13

Add the two equations: 2x = 26, so x = 13 and y = 7. Check: 13 + 7 = 20 and 13 − 7 = 6. This method of adding the equations to remove one unknown is called elimination.

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Answer and explanation

The correct answer is A. 13

Add the two equations: 2x = 26, so x = 13 and y = 7. Check: 13 + 7 = 20 and 13 − 7 = 6. This method of adding the equations to remove one unknown is called elimination.

Topic: Algebra and Equations MCQs · Subject: Numerical Ability