Đáp án:
(5x - 2)³ + (2 - 5x)(3x + 1) = 0
⇔ (5x - 2)³ - (5x - 2)(3x + 1) = 0
⇔ (5x - 2)[(5x - 2)² - (3x + 1)] = 0
⇔ (5x - 2)(25x² - 20x + 4 - 3x - 1) = 0
⇔ (5x - 2)(25x² - 23x + 3) = 0
TH1. 5x - 2 = 0
⇔ x = $\frac{2}{5}$
TH2. 25x² - 23x + 3 = 0
⇔ x = $\frac{23±\sqrt{229}}{50}$