Cho 20 diem,trong do co a diem thang hang,cu 2 diem,ta ve 1 duong thang.Tim a,biet ve duoc tat ca 171 duong thang

cho 20 diem phan biet trong do co dung 7 diem thang hang ngoai ra khong co ba diem thang  hang cu qua hai diem ta ve duoc mot duong thang hoi tu  20 diem do ve duoc tat ca bao ngieu duong thang

giúp mình với

cho 50 diem trong do co dung m diem thang hang , ngoai ra ko co 3 diem naop thang hang. cu qua 2 diem ta ve duoc 1 duong thang .so duong thang ve duoc la 1215 duong thang.tim m

cho 20 diem , trong do co a thang hang . Cu 2 diem , ta ve mot duong thµg .Tim a , niet ve duoc tat ca 170 duong thang.

Cho 20 diem , trong do co A  diem thang hang , co 2 diem la ta ve 1 duong thang  .Tim A biet duoc tat ca 170 duong thang 

1. Tren 1 duong thang xy lay 4 diem phan biet A,B,C,D hay chi ra cac tia doi nhau 

2. cho 10 diem trong do khong co ba diem thang hang . Cu qua hai diem ta ve duoc 1 duong thang . Hoi co tat ca bao nhieu duong thang?

3. cho n diem trong do khong co ba diem nao thang hang . Cu qua hai diem trong so cac diem do ve duoc 1 duong thang. Biet rang co 435 duong thang tao thanh .Tim n?

cho n diem trong do ko co 3 diem nao thang hang . cu qua 2 diem ta ve duoc 1 duong thang . biet rang co tat ca 105 duong thang . tinh n?

cho 20 diem trong do co A diem thang hang . Cu 2 diem ta ve duoc 1 duong thang . tim A biet ve duoc 170 duong thang

cho 12 diem phan biet trong do co dung 4 diem thang hang. cu qua 2 diem ve duoc 1 duong thang. hoi tat ca co bn duong thang?