1/ => 2x + 1 = 0 => 2x = -1 => x = -1/2
hoặc 3x - 9 = 0 => 3x = 9 => x = 3
Vậy x = { -1/2 ; 3 }
2/ => x2 = 0 => x = 0
hoặc 2/3 - 5x = 0 => 5x = 2/3 => x = 2/15
Vậy x = 2/15 ; x = 0
3/ 2x - 7 = 7 - 2x
=> 2x + 2x = 7 + 7
=> 4x = 14
=> x = 7/2
Vậy x = 7/2