2 4x 9 2x 4 0 July 8, 2019 16 32 64 128 4x 2 9 2x 3 x 4 0 Tìm x biết 4x 2 9 3 2x x 4 0 2x 9 2x ^ 4 - 9x ^ 2 + 4 = 0