If 3^(x + y) = 81 and 81^(x – y) = 3, find the value of x.

Topic: Algebra
Subtopic: Exponents

A17/8

B15/8

D5/2

Explanation

3^(x+y) = 3^4 => x + y = 4. (3^4)^(x-y) = 3^1 => 4(x – y) = 1 => x – y = 1/4. Adding both equations: 2x = 4 + 1/4 = 17/4 => x = 17/8.

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