Answer
$y_2-y_1$;
$x_2-x_1$
Work Step by Step
RECALL:
The formula for the slope of a line is given by
$\dfrac{y_2-y_1}{x_2-x_1}$
where $(x_1, y_1)$ and $(x_2, y_2)$ are two points on the line.
Thus, the missing expressions in the given statement (in order) are:
$y_2-y_1$;
$x_2-x_1$
