If 2^(x - 1) + 2^(x + 1) = 320, find the value of x.

Answer and explanation

Correct answer: B. 7

  1. Step 1: Factor out 2^x: 2^x [2^(-1) + 2^1] = 320.
  2. Step 2: 2^x [1/2 + 2] = 2^x (5/2) = 320.
  3. Step 3: 2^x = 320 (2/5) = 64 2 = 128.
  4. Step 4: 2^x = 2^7 => x = 7.

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If 2 (x - 1) + 2 (x + 1) = 320, find… | CAT Powers and roots