Himpunan penyelesaian dari |x-1|+|2x|+|3x+1|=6

|x-1|+|2x|+|3x+1|=6
x-1+2x+3x+1 = 6
6x = 6
x = 1

x-1+2x+3x+1= -6
6x = -6
x = -1

HP = {(-1,1)}