This is the concept of algebra, to solve the inequality we proceed as follows;
|8m+4|<12
given that the absolute value is represented by positive and negative values, we shall have:
-(8m+4)<12
-8m-4<12
-8m<12+4
-8m<16
thus;
m>16/(-8)
m>-2
also:
8m+4<12
8m<12-4
8m<8
m<8/8
m<1
hence the answer is -2<m<1