Answer and explanation

Correct answer: A. 6

  1. Step 1: Write 128 as a power of 2: . Step 2. Equate the indices: , so . Answer: 6. Why not the others: 7: That ignores the in the index. 8: That adds 1 where it should be subtracted. 7/2: That divides the power by 2.

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Solve 2 x+1 = 128 for x. | Singapore GCE O-Level