The equation for working out the slope of a linear line is: [tex] \frac{y_2 - y_1}{x_2 - x_1} [/tex], where x and y are the coordinate pairs.
So just pick two of the purple dots on the graph and fill in the equation.
I'll pick the dot that's (-4, 1) and (4, -7).
Now I just do [tex] \frac{7 - 1}{4 - -4} [/tex], which is just [tex] \frac{3}{4} [/tex] when simplified.
