∵M为BC的中点,∴BM=MC,
且∠BME=∠CMF(对顶角),∠BEM=∠CFM(内错角),∴△BME≌△CMF,
∴CF=BE=3/4AB
又∠ANE=∠CNF(对顶角),∠AEN=∠CFN(内错角),∴△ANE∽△CMF,
而AE=AB+BE=7/4AB
∴S△CNF:S△ANE=CF²/AE²=3²/7²=9/49
∵M为BC的中点,∴BM=MC,
且∠BME=∠CMF(对顶角),∠BEM=∠CFM(内错角),∴△BME≌△CMF,
∴CF=BE=3/4AB
又∠ANE=∠CNF(对顶角),∠AEN=∠CFN(内错角),∴△ANE∽△CMF,
而AE=AB+BE=7/4AB
∴S△CNF:S△ANE=CF²/AE²=3²/7²=9/49