x + 120 =500+560 x + 345 =678-321
x+120 = 1060 x + 345 =357
x =1060-120 x = 357-345
x = 940 x = 12
x+120=500+560
x=940
x+345=678-321
x=12
ket qua chuan luon do ban nho k cho minh nha
x+120=500+560
x+120=1060
x=1060-120
x=940
x+345=678-321
x+345=357
x=357-345
x=12