X + 10 = 50 - 10
X + 10 = 40
X = 40 - 10
X = 30
Ai k mk mk k lại
X + 10 = 50 - 10
X + 10 = 40
X = 40 - 10
X = 30
X + 10 = 50 - 10
X + 10 = 40
X = 40 - 10
X = 30
X + 10 = 50 - 10
X+ 10 = 40
X = 40 - 10
X = 30
X + 10 = 50 -10
X + 10 = 40
X = 40 - 10
X = 30
X+10=50-10
X+10=40
X =40-10
X = 30