x+20=500+900
x+20=1400
x = 1400-20
x = 1380
k mik nha
x + 20 = 500 + 900
x + 20 = 1400
x = 1400 - 20
x = 1380
x + 20 = 500 + 900
x + 20 = 1400
x = 1400 - 20
x = 1380
x + 20 = 500 + 900
x + 20 = 1400
x = 1400 - 20
x = 1380
.k cho mình nha
ta có : x + 20 = 1400
x = 1400 - 20
x = 1380
x + 20 = 500 + 900
x + 20 = 1400
x = 1400 - 20
x = 1380
x+20=1400
x=1400-20
x=1380
k minh nha minh trang