#### Fundamental of Solving Exponential and Logarithm Functions

- In solving equations, the most important identity of both exponential and logarithmic functions are that they are one-to-one functions. In other words,

a^{x}=a^{y} or \log_{a}{x}=\log_{a}{y} implies that x=y.

Example

3^{x-1}=81=3^{4}