解答：证明：（1）∵AD?AB=AE?AC，∴AD：AE=AC：AB，∵∠A=∠A，∴△ABE∽△ACD；（2）∵△ABE∽△ACD，∴∠ABE=∠ACD，∵∠BFD=∠CFE，∴△BFD∽△CFE，∴FD：FE=FB：FC，∴FD?FC=FB?FE．
