Official Guide Explanation:
Problem Solving #128




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Solution and Metadata

Question: 128
Page: 78
Difficulty: 5 (Moderate)
Category 1: Algebra > Simplifying Algebraic Expressions >

Explanation: This is a textbook example of isolating a variable. Remember, the first step is to get rid of fractions, followed by moving all terms containing the relevant variable to one side, then factoring out that variable. Those steps are as follows:

((x + y)/(xy)) = 1

x + y = xy

x = xy - y

x = y(x - 1)

y = ((x)/(x - 1)), choice (A).

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