Then it can be written as $f(x) = mx + b$ where $m$ and $b$ are real numbers and $m \neq 0$. Let $x_1$ and $x_2$ represent any two values in the domain of $f$ such that $x_1 \neq x_2$. Then the average rate of change between $x_1$ and $x_2$ is given by
Show more…