... ctra hinh ch6p ^S' .1& apos;B' C' D' theo a, v&i ,S' h tam cfu hinh w0ng ABCD 'CiuV (1, 0tli6m)Xicdinh m saocho xa -2 x3 +8**l)*&apos ;-2 mx+m&apos ;-4 > ;A, ... (1) viL Q)suy ra G, = Grhay AA',BB',CC' vd DD' d6ng quy.Tt gia thii5t ta suy ra A& apos;B'll =Jrcn, B'C'll =!ne,C'D'll =Iut2 ' ... +8*+l)x2 -Zmx+m'*4> -a, vxe[ *1, 1]<>(*' - * * *f r-4vx e [*r,r]o Hfi(r' - * * *)' > 4. (3)DAt t = xt -x, tac6 t'=2x-I.xl I^ l -1 : 1 'rt'l...