## Thinking Mathematically (6th Edition)

$m=\dfrac{y_2-y_1}{x_2-x_1}$
RECALL: The slope $m$ of a line can be found using the formula: $m=\dfrac{y_2-y_1}{x_2-x_1}$ where $(x_1, y_1)$ and $(x_2, y_2)$ are points on the line. Thus, the missing expression in the given statement is: $m=\dfrac{y_2-y_1}{x_2-x_1}$