Step-by-step explanation:
We have been given that AE=BE and .
We can see that angle CEA is vertical angle of angle DEB, therefore, as vertical angles are congruent.
We can see in triangles CEA and DEF that two angles and included sides are congruent.
or
Therefore, by ASA postulate.
Since corresponding parts of congruent triangles are congruent, therefore CE must be congruent to DE.