You can find the slope using the slope formula, y_2 - y_1 / x_2 - x_1 , where the y- and x- values are your coordinates.
y_2 - y_1 / x_2 - x_1 Plug in the values
4 - 3 / 2 - (-1) Cancel out the double negative
4 - 3 / 2 + 1 Add and Subtract
1 / 3
The slope of the line is 1/3.