It is known that in the triangle ABC, AB is greater than AC, the bisector of angle B intersects d with the bisector of the outer angle of angle c, DF parallels BC, and AB and AC intersect F and e respectively BF=EF+CE.

It is known that in the triangle ABC, AB is greater than AC, the bisector of angle B intersects d with the bisector of the outer angle of angle c, DF parallels BC, and AB and AC intersect F and e respectively BF=EF+CE.

Set point G on the extension line of BC
Known, DF ‖ BC,
It can be concluded that: ∠ FDB = ∠ CBD = ∠ FBD, ∠ EDC = ∠ GCD = ∠ ECD,
So BF = DF, CE = De,
BF = DF = EF + de = EF + CE