<s>[INST] In the given figure, $ABCD$ is a rectangle where $DE = DF$ and $AE = AF$. Since the two right-angled triangles, $\triangle AED$ and $\triangle ABF$, are similar, we can set up the following proportion: $\frac{AE}{AB} = \frac{DE}{BF}$ (a) Find the value of $x$. (b) Find the value of $y$.[/INST]