1. (2x + 3)(x - 1)+(2x - 3)(1 - x)=0
(2x + 3)(x - 1)- ( 2x -3)( x-1) =0
(x-1)( 2x +3 - 2x +3) =0
(x -1) . 6 =0
x-1 =0
x =1
2) ( 5x - 4)² - 49² =0
(5x-4-49)( 5x-4+49) =0
(5x - 53)( 5x+45) =0
=> 5x-53 =0
hoặc 5x+45 =0
+) 5x-53 =0
5x =53
x = 53/5
+) 5x-45=0
5x =45
x =9
3) x² +3x -10 =0
x² +5x -2x -10 =0
x( x+5) - 2( x+5)=0
(x-2)(x+5) =0
=> x-2 = 0
hoặc x+5 =0
+) x-2 =0
x = 2
+) x+5 =0
x =-5