Question

[nguyen ho duong thang]

cho tam giac vuong can abc . Tren canh AB lay diem M sao cho BM=2MA tren nua mat phat phang bo ab khong chua diem C ve duong thang Bx vuong goc voi AB , tren Bx lay diem N sao cho BN=1/2AB.Duong thang MC cat NA tai E, duong thang BE cat duong thang AC o F.CMR: AF=AM