7x 1 2x 2 6x và 5 3x x 2 9 July 8, 2019 16 32 64 128 2x 7 7 - 11x 9x - 2(5x + 7) 6-x 2(1-4x)-3(1-3x) 7. 1) 2x ^ 2 - 7x + 6 = 0 3) 5x ^ 2 - 12x + 4 = 0
