Variant 7.6.1. On a plane, points $A, B, C, D, E$ were marked such that triangles $A B C$ and $A D E$ are equal: $A B=A D, A C=A E, B C=D E$. Then, point $E$ and the labels of points $B, C$, and $D$ were erased from the drawing.

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Let point $E$ have coordinates $(x ; y)$.

(a) (1 point) Indicate any possible value of the quantity $x y$.

(b) (3 points) Indicate all possible values of the quantity $x y$.
Answer: (a) any of the numbers $14,18,40$. (b) $14,18,40$.