The slope formula is slope = y2 - y1 / x2 - x1 and the variables are found by assigning them with their corresponding values. Here, x1 = -9, x2 = -13, y1 = 18, and y2 = 5. Next, substitute these values in and get 5 - 18 / -13 - (-9). This can fully simplify to 13 / 4 or 3.25.
