x - 105 : 21 = 15
x - 105 = 315
x =420
tk mk nhé
x - 105 ÷ 21 = 15
x - 5 = 15
x = 15 + 5
x = 20
C1: x - 105 : 21 = 15
x - 5 = 15
x = 15 + 5
x = 20
x -105 :21 = 15
x - 5 = 15
x = 15 + 5
x = 20
Hok giỏi
x-105:21=15
x-105=15x21
x-105=315
x =315+105
x =420