| x + 1 | + 3| x - 1 | = x + 2 + | x | + 2| x - 2 |
Ta có 4 TH
Th1:
x≥2
x + 1 + 3( x - 1) = x + 2 + x + 2(x - 2)
x + 1 + 3x - 3 = 2x + 2 + 2x - 4
4x - 2 = 4x - 2 (vô số nghiệm)
Th2:
-1<x<2
x + 1 + 3(x - 1) = x + 2 + x + 2( 2 - x)
x + 1 + 3x - 3 = 2x + 2 + 4 - 2x
4x - 2 = 6
4x = 4
x = 1
Th 3
x≤-1
1 - x + 3(1 - x) = x + 2 - x + 2(2 - x)
1 - x + 3 - 3x = 2 + 4 -2x
4 - 4x = 6 - 2x
-2x = 2
x = -1
