Đặt x^2 + 5x = t
pt <=> t + 2 = \(2\sqrt[3]{t-2}\)
=> ( t+ 2 )^3 = \(8\left(t-2\right)\)
=> t^3 + 6t^2 + 12t + 8 - 8t + 16 = 0
=> t^3 + 6t^2 + 4t + 24 = 0
=> ( t + 6 ) ( t^2 + 4 ) = 0
=> t = -6 ( t^2 + 4 > = 0 )
(+) x^2 + 5x = -6
=> x^2 + 5x + 6 = 0
tự giải nha