x + 80 = 80 + 20
x + 80 = 100
x = 100 - 80
x = 20
x + 80 = 80 + 20
x + 80 = 100
x = 100 - 80
x = 20
Vậy x = 20
x + 80 = 80 + 20
x + 80 = 100
x = 100 - 80
x = 20
ai tk mk mk tk lại
x+ 80 = 80 + 20
X + 80 = 100
X = 100-80
X = 20
X + 80 = 80 + 20
x + 80 = 100
x = 100 - 80
x = 20