Maths problem: how to do, thanks.?

△FBC 等邊, 故等角, 故 ∠FBC = 60°
□ABCD 是正方形, 所以 ∠ABF = 30°.
BF = BC = BA,
所以 △BFA 等腰,
∴ ∠AFB = ∠FAB = (180°-30°)/2 = 75°
∴ ∠AFE = 180° - 60° - 75° = 45°