x + 2000 - 3000 = 1900
x + 2000 = 1900 + 3000
x + 2000 = 4900
x = 4900 -- 2000
x = 2900
rồi đó tk nha
X+2000-3000=1900
x+2000=1900+3000
x+2000=4900
x=4900-2000
x=2900
x+2000-3000=900x2+100
x+2000-3000=1800+100
x+2000-3000=1900
x+2000 =4900
x =2900
vậy x=2900.
x = 2900
tk mk nha bn mk tk cho bn rồi đó