Tìm x thuộc Z, biết: 1. 2 |x - 1| - 5(x + 3) - 2(x-7) = |x - 1|- 7x 2. |x - 2| - 5(x - 4) =20 - 5x 3. 4(x - 2) - 3(x + 4 =(-4)(+3)(-125)(+25)(-8) 4. -3(2x - 4) + 7(x-5) = (-67)(1-301) - 301 . 67 5. 7(x - 5) - 4(x+3) = 2(x - 5)+ (13-135 + 49 ) - (13+49) 6. 5(x-3) - 2(x + 1)= 3 + 2(x-1)+(18 + 29) +( 185 - 18 - 29)