a) (2x+10)(x2+3)=0
(1) 2x+10=0 (2) x2+3=0
=> 2x=0+10 =>x2=0-3
=> 2x=10 =>x2=-3(Loại)
=>x=10:2
=>x=5
Vậy x=5
b)-12(x-5)+7(3-x)=5
-12.x+12.5+7.3+7.(-x)=5
-12.x+60+21+7.(-x)=5
-12.x+60+21+(-7).x=5
[(-12)+(-7)].x+60+21=5
-19x+81=5
-19x=5-81
-19x=-76
x=-76:(-19)
x=4
Vậy x=4.
| 2x - 5 | = 13
=> 2x - 5 = -13
Hoặc 2x - 5 = 13
+) 2x - 5 = -13
2x = ( -13 ) + 5
2x = -8
x = ( -8 ) : 2
x = -4
+) 2x - 5 = 13
2x = 13 + 5
2x = 18
x = 18 : 2
x = 9.
Vậy x=-4 hoặc x=9