(2x + 5).(4x2 - 9) = 0
(2x + 5).(4x² - 9) = 0
<=> (2x + 5)(2x + 3)(2x - 3) = 0
TH1: 2x + 5 = 0 => x = -5/2
TH2: 2x + 3 = 0 => x = -3/2
TH3: 2x - 3 = 0 => x = 3/2
Vậy x = {-5/2 ; 3/2 ; -3/2}
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