X + 400 = 2000 - 400
X + 400 = 1600
X = 1600 - 400
X = 1200
X + 400 = 2000 - 400
X + 400 = 1600
X = 1600 - 400
X = 1200
x+400=2000-400
X+400=1600
X=1600-400
X=1200
con gái ủng hộ nha
X + 400 = 2000 - 400
X + 400 = 1600
X = 1600 + 400
X = 200
X + 400 = 2000 - 400
X + 400 = 1600
X = 1600 + 400
X = 200
X+400=2000-400
X+400=600
X=600-400
X=200
X + 400 = 2000 - 400
X + 400 = 1600
X = 1600 + 400
X = 200
X + 400 = 2000 - 400
X + 400 = 1600
X = 1600 + 400
X = 200
x+400=2000-400
x+400=1600
x=1600-400
x=1200
x+400=2000-400
x+400=1600
x =1600-400
x =1200