Y 9 =- 3 4 x 4 July 8, 2019 16 32 64 128 Y x 3 6x 2 4m 9 x 4 nghịch biến Y x 3 6x 2 4m 9 x 4 4) 9 4 3 y − = 9 4 3 y − = 4) 9/(y - 4) = 3