... B ( 2x o +11) x o + ứ ố IA = IB = 2x o + ị IA.IB = 12 < /b> x o +1 1,0 0 ,25< /b> 0 ,25< /b> B nkớnh r= IA.IB IA.IB IA.IB = Ê = 2 < /b> IA + IB + AB IA + IB + IA +IB IA.IB + 2IA.IB + 0 ,25< /b> Du=xyrakhivchkhi IA = IB ... ABB ' A ' Suyra: ) d ( A ' B, CC ') = d ( CC ', ( ABB ' A ' ) ) = d ( C , ( ABB ' A ' )=CH ) S DABC = ã a2 AC.BC s in 120< /b> = 2 < /b> AB = AC + BC - AC.BC.cos 120< /b> 0 = a ị AB = a 0,5 2.< /b> DABC a 21< /b> S = AB ... (013), IB = (0 -1 -3) ị IA = - IB ị IA + IB = AB 0 ,25< /b> 0 ,25< /b> 2 < /b> 1ổ1 1 2< /b> Khiú MA + MB ( MA2 + MB ) ỗ ( MA + MB ) ữ AB = ( IA + IB ) 2< /b> 2 < /b> ứ 4 ị MA +MB nhnhtkhiMtrựngviI (2 < /b> - 10) VIIb 0 ,25< /b> z + i...