**What are logarithms used for?** Logarithms are used for *expressing the exponent to which a given number must be raised to get another number.* **If $a$ needs to be raised to the power of $b$ in order to equal $x$, how do we express that with a logarithm?** If $a$ needs to be raised to the power of $b$ in order to equal $x$, we express that with a logarithm by writing: $\log_a x=b$ **What equation is $\log_a x=b$ equivalent to?** $log_a x=b$ is equivalent to: $a^b=x$ ...