Solving Equations with Logs

Type 1: logax = b

Convert to index form: x = ab

Example: log2x = 5   ⇒   x = 25 = 32

Type 2: Same base both sides

If logax = logay then x = y

Example: log x + log 2 = log 14   ⇒   log(2x) = log 14   ⇒   2x = 14   ⇒   x = 7

Check: The argument of every log must be positive in the final answer.

Discussion

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Related Exercises

Solve for x

Solve (base 10 unless shown):log x = 2log3x = 4log x + log 5 = 1log2x - log23 = 22 …

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