In any triangle ABC:
AB+BC>AC; AB+AC>BC; AC+BC>AB. (The sum of the lengths of any two sides is greater than the length of the remaining side.)
So AB<AC+BC, so AB>AC+BC is false. BC<AB+AC, so BC>AB+AC is also false.
AB+AC=BC+AC, AB=BC (given), so AB+AC=BC+AC is true.
AB+BC=AB+AC, 2AB=AB+AC, AB=AC is false (in general) since only two sides AB and BC are given to be equal. If it were true ABC would be an equilateral triangle AB=BC=AC.