Exercise 13.3.3

Suppose that the black-height of each of the subtrees $\alpha$, $\beta$, $\gamma$, $\delta$, $\epsilon$ in Figures 13.5 and 13.6 is $k$. Label each node in each figure with its black-height to verify that the indicated transformation preserves property 5.

This is kinda obvious. You can see that regardless of the transformation, there is always only one black parent above the subtree in the figure.