Answer:
Step-by-step explanation:
The slope of the line passing through two given points: [tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
K(c + d, c-d) ⇒ x₁ = c + d, y₁ = c - d
L(c-d, c+ d) ⇒ x₂ = c - d, y₂ = c + d
So, the slope:
[tex]m=\dfrac{c+d-(c-d)}{c-d-(c+d)}=\dfrac{c+d-c+d}{c-d-c-d}=\dfrac{2d}{-2d}=-1[/tex]