Final answer:
To find the slope between two points, use the formula (y2 - y1) / (x2 - x1). For (5, 5) and (5, -2), the slope is undefined. For (8, -1) and (0, 15), the slope is -2 and the y-intercept is 15.
Step-by-step explanation:
In order to find the slope between two points (x1, y1) and (x2, y2), we use the formula: slope = (y2 - y1) / (x2 - x1).
For the first set of points, (5, 5) and (5, -2), the x-coordinates are the same, meaning that there is no horizontal change. Thus, the slope is undefined.
For the second set of points, (8, -1) and (0, 15), we can use the slope formula to find the slope = (-1 - 15) / (8 - 0) = -16 / 8 = -2.
The y-intercept can be determined using the equation of a straight line, y = mx + b, where m is the slope and b is the y-intercept. Plugging in one set of points, we get -1 = (-2)(8) + b, which gives us b = 15.