Solve .

Answer and explanation

Correct answer: D. or

  1. Step 1: Let . Then , so .
  2. Step 2: Factorise: , so or .
  3. Step 3: gives ; gives .
Answer
or .
Why not the others: or : finds the values of but does not convert them into values of . or : treats as . or : takes the logarithm of the coefficients rather than solving the quadratic.

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