In the overlapping triangles $△ABC$ and $△ABE$ sharing common side $AB$, $\angle EAB$ and $\angle ABC$ are right angles. If $AB=5$, $BC=4$, $AE=10$, and $\overline{AC}$ and $\overline{BE}$ intersect at $D$, what is the difference between the areas of $△ADE$ and $△BDC$?
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