khi chia số tự nhiên a cho các số.6,7;8 thì được tổng các số dư là.18. Hỏi số a chia cho 28 dư bao nhiêu

one of my favourite sports is soccer. I have played it since i was 7 years old. At that time, when i saw the boys playing football, my heart was excited. I immediately ran home, asked my mother to buy a ball and i asked my father to show me to play At first, i thought soccer was easy but after a few day i found it harder than i though because we need a quick and skillful food. To continue my hobby i have to practice every day I will try to become a soccer player in the future. This is my favourite sport and thank to soccer my stamina is better Bài này mình làm có được ko ạ

tìm n,x thuộc Z để các p/s sau có GTNN: 2x+4/x+1