Problem 9.6. The graph of the line $y=k x+l$ intersects the $O x$ axis at point $B$, the $O y$ axis at point $C$, and the graph of the function $y=1 / x$ at points $A$ and $D$, as shown in the figure. It turns out that $A B=B C=C D$. Find $k$, given that $O C=3$.

![](https://cdn.mathpix.com/cropped/2024_05_06_1f4981519479532effc1g-05.jpg?height=621&width=622&top_left_y=83&top_left_x=416)