The slope of a line passing through two given points A(x₁, y₁) and B(x₂, y₂) is given by:

1. $m = \dfrac{x$2 - x1}{y2 - y1}

2. $m = \dfrac{y$2 \times y1}{x2 \times x1}

3. $m = \dfrac{x$2 \times x1}{y2 \times y1}

4. $m = \dfrac{y$2 - y1}{x2 - x1}

The correct formula for slope is: $m = \dfrac{y$2 - y1}{x2 - x1}

Hence, option 4 is the correct option.