How to evaluate rational expressions - PSAT Math
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Question
If √(ab) = 8, and _a_2 = b, what is a?
If √(ab) = 8, and _a_2 = b, what is a?
Answer
If we plug in _a_2 for b in the radical expression, we get √(_a_3) = 8. This can be rewritten as a_3/2 = 8. Thus, log_a 8 = 3/2. Plugging in the answer choices gives 4 as the correct answer.
If we plug in _a_2 for b in the radical expression, we get √(_a_3) = 8. This can be rewritten as a_3/2 = 8. Thus, log_a 8 = 3/2. Plugging in the answer choices gives 4 as the correct answer.
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