problem
Okay, we know that CE+BC>BE (I don't know what you call rule, but its when the sum of 2 sides of a triangle are greater then the length of third side)
ANd we know that AE=AC+CE, or, AE-AC=CE by subtracting AC from both sides.
Now since AC=BC, then AE-BC=CE.
Now since we know CE+BC>BE, and AE-BC=CE, substitute in CE, giving you AE-BC+BC>BE, or, AE>BE, we is what we set out to prove!
I hope this helps!