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Treating a logarithm as division

A logarithm asks for an exponent. Rewrite the statement as a power of the base.

Spot the wrong turn

Find log₂(32).

Incorrect answer: 16

A logarithm can be negative even though its argument must be positive. log₁₀(0.01) is −2, but log₁₀(−2) is not defined in the real numbers.

Work it through

The correction

5

2⁵ = 32.

  1. Identify the base, argument, and unknown exponent.
  2. Translate log_b(a) = c into b raised to c equals a.
  3. Evaluate or solve, then check that every original logarithm has a positive argument.

Try the reasoning in another example

Find log₁₀(0.01).

  1. 0.01 is 1/100.
  2. 10 raised to −2 equals 1/100.

Answer: −2

Explain why each step preserves the quantity or relationship. If you can compute the answer but cannot explain the step, revisit the model before adding more questions.

The short check below reuses the first example as a retrieval question and adds a second question. It checks this method; it does not establish a grade level.

Your next step

Check this step for yourself

2 questions · No time limit

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1 Find log₂(32).
2 Solve log₅(x) = 2.