Đáp án:
`3 (2x - 1) (x + 2) - 2 (3x + 2) (x - 4) = 5`
`⇔ 3 [(2x - 1) (x + 2)] - 2 [(3x + 2) (x-4)] = 5`
`⇔ 3 [2x (x + 2) - 1 (x + 2)] - 2 [3x (x-4) + 2 (x-4)] = 5`
`⇔ 3 [2x^2 + 4x - x - 2] - 2 [3x^2 - 12x + 2x - 8] = 5`
`⇔ 3 [2x^2 + 3x - 2] - 2 [3x^2 - 10x - 8] = 5`
`⇔ 6x^2 + 9x - 6 - 6x^2 + 20x + 16 = 5`
`⇔ (6x^2 - 6x^2) + (9x + 20x) + (-6 + 16) = 5`
`⇔ 29x + 10 = 5`
`⇔ 29x=5-10`
`⇔29x =-5`
`⇔x=-5 ÷ 29`
`⇔x=(-5)/29`
Vậy `x=(-5)/29`
