x + 40 = 50 + 20
x + 40 = 70
x = 70 - 40
x = 30
x+40=50+20
x+40=70
x=70-40
x=30
x + 40 = 50 + 20
x + 40 = 70
x = 70 - 40
x = 30
x+40=50+20
x+40=70
x =70-40
x =30.
Ai tk mk mk tk lại!
x + 40 = 50 + 20
x + 40 = 70
x = 70 - 40
x = 30
x + 40 = 50 + 20
x + 40 = 70
x = 70 - 40
x = 30