xét x<1:
=>-(x-1)-(x-3)+4-x=2x-3
=>-x+1-x+3+4-x=2x-3
=>-3x+8=2x-3
=>-3x-2x=-3-8
=>-5x=-11
=>x=11/5 (loại)
xét 1<(=)x<(=)3:
=>x-1-(x-3)+4-x=2x-3
=>x-1-x+3+4-x=2x-3
=>-x+6=2x-3
=>6+3=3x
=>9=3x
=>x=3
xét 3<x<(=)4:
=>x-1+x-3+4-x=2x-3
=>x=2x-3
=>x=3 (loại)
xét x>4:
=>x-1+x-3-(4-x)=2x-3
=>2x-4-4+x=2x-3
=>3x-8=2x-3
=>3x-2x=8-3
=>x=5 (chọn)
vậy x=3;5