... VDCSB = VS ABCD ị VDPQCNB = VSABNPQ 7 VS ABCD ị VSABNPQ = VS ABCD ị = 12 12 VDPQCNB Cõu V: T gi thit x + y + z2 = ị < x , y, z < ã p dng BT Cụsi cho s dng: x ,1 - x - x ta c: Trn S Tựng x + (1 ... 2(7-k ) 2k S hng cha x 2(7 - k ) = k = k =0 ị H s ca x l: C7 23 = 280 Theo chng trỡnh nõng cao Cõu VI.b: 1) Gi I, I1, I2, R, R1, R2 ln lt l tõm v bỏn kớnh ca (C), (C1), (C2) Gi s I(a; a ...