Worked solution
Write down the two points
Label the first point (x_1, y_1) and the second (x_2, y_2). Keeping them in order stops sign mistakes later.
Recall the gradient formula
The gradient measures steepness: how much the line goes up (or down) for each step to the right. This is the change in y divided by the change in x.
Substitute the coordinates
Carefully put each number in its place. Subtracting a negative becomes adding, so watch those double signs.
Simplify to find the gradient
Work out the top and bottom, then simplify the fraction. A positive answer slopes uphill, a negative one slopes downhill.