Cho P la so nguyen to lon hon 3 va 5p+1 cung la so nguyen to. Chung minh rang 7p+1 la hop so
a) Cho p va p+2 la cac so nguyen to ( p > 3 ) . Chung minh rang p + 1 chia het cho 6
b) Cho p va p + 4 la cac so nguyen to ( p > 3 ) . Chung minh rang p + 8 la hop so
1) Mot so nguyen to chia cho 30 duoc so du la r.Tim r,biet r khong phai la so nguyen to.
2) Chung minh rang:
a/ So 17 khong viet duoc tong 3 hop so khong bang nhau.
b/Moi so le lon hon 17 deu viet duoc duoi dang 3 hop so khac nhau.
cho p va p+8 la so nguyen to(p>3).chung minh rang:8p-1 la hop so
cho 2p+1 va p la so nguyen to (p>3) chung minh rang 4p+1 la hop so
chung to rang so nguyen to p;p>5 khi chia cho 6 co the du 1 hoac 5
2)chung minh rang neu p va p+2 la so nguyen to lon hon 3 thi p+1 la mot hop so
cho p la so nguyen to lon hon 3
a] chung to rang p 6k+1 hoac 6k+5
b] biet 8p +1 la so nguyen to chung minh 4p+1 la hop so
cho p va 2p+1 la so nguyen to (p>3).chung minh rang:4p+1 La hop so
Cho p;p +14 la mot so nguyen to. Chung minh rang p + 7 la hop so
