Rewrite as an equation.

Rewrite in exponential form using the definition of a logarithm. If and are positive real numbers and does not equal , then is equivalent to .

Create expressions in the equation that all have equal bases.

Rewrite as .

Since the bases are the same, then two expressions are only equal if the exponents are also equal.

Solve for .

The variable is equal to .

The result can be shown in multiple forms.

Exact Form:

Decimal Form:

Evaluate log base 81 of 3