Answer:
Step-by-step explanation:
The formula of a slope:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We have the points N(1, -4) and M(-1, 4). Substitute:
[tex]m=\dfrac{4-(-4)}{-1-1}=\dfrac{8}{-2}=-4[/tex]