|2x+1|-19=-7
|2x+1| =-7+19
|2x+1| =12
=>2x+1=12 hoặc 2x+1=-12
2x=12-1 2x=-12-1
2x=11 2x=-13
x=11:2 x=-13:2
x=11/2 x=-13/2
Vậy x=11/2 hoặc x=-13/2
Ư(10)={1;2;5;10}
BC(-15)={0;1;2;3;......-1;-2;-3.....}
Ư(-24)={1;2;3;8,6,4;24;-1;-2;-3;-4;-6;-8;-24}
ƯC (-12;18)={1,2,3,4,6,12,18,-1,-2,-3,-4,-6,-12,-18}
BC(-15,+20)={1,3,5,-1,-3,-5}