Practice Logarithm Properties in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The three fundamental rules of logarithms: the product rule \log_b(xy) = \log_b x + \log_b y, the quotient rule \log_b\!\left(\frac{x}{y}\right) = \log_b x - \log_b y, and the power rule \log_b(x^n) = n\log_b x.

Logarithms were invented to turn hard operations into easy ones. Multiplication becomes addition, division becomes subtraction, and exponentiation becomes multiplication. This is why slide rules workedβ€”they added lengths (logarithms) to multiply numbers.

Example 1

easy
Expand \log_2(8x^3) using logarithm properties.

Example 2

medium
Condense 2\ln x - \frac{1}{2}\ln(x + 1) + 3\ln y into a single logarithm.

Example 3

medium
Use the change of base formula to evaluate \log_3 20 to three decimal places.

Example 4

easy
Expand \log\left(\frac{a^2}{b^5}\right).