chay trdn dudng trdn (O). Do dd H phaichay trdn dudng trdn (C) la anh cua (O)qua
phep dd'i xiing qua dudng thang BC.Hmh 1.9C. CAU HOI
VA BAI TAP1.6. Trong mat phang toa dd Oxy, cho dilm M(3 ; -5), dudng thang d cd phuong tnnh3x + 23^ - 6 = 0
va dudng trdn (C) cd phuong txinh : x[r]