Vì p là số nguyên tố => p >1.
Ta có : 8p-1;8p;8p+1 là 3 số tự nhiên liên tiếp
=> (8p-1)8p(8p+1) chia hết cho 3
Mà 8p-1;8p+1 là số nguyên tố >3 = > 8p chia hết cho 3
=> p cha hết cho 3
=> 8p+1=25 k nguyến tố
vậy p thuộc rỗng
cho so nguyen to p va mot trong hai s 8p+1 va 8p-1 la so nguyen to ,so con lai la so nguyen to hay hop so?
cho p la so nguyen to lon hon 3. Biet 8p+1 va p deu la so nguyen to (p lon hon 3).Hoi p+100 la so nguyen to hay hop so
bai 3 cho p la so nguyen to lon hon 3
A, chung to p co dang 6k+1 hoac 6k+5
B, cho p va 8p-1 la so nguyen to. chung to 8p+1 la hop so
bai 4
A, tim a va b biet rang a.b=320 va BCNN(a,b)=160
B, tim so tu nhien a nho nhat co 3 chu so sao cho khi chia a cho 11 du 5 va chia cho 13 thi du 8
Cho P va 8P-1 la so nguyen to (p>3)
Hoi 8P+1 la so nguyen to hay hop so.
Cho p va 8p -1 la so nguyen to . Chung minh 8p+1 la hop so
tim so nguyen to p sao cho 8p+1 la so chinh phuong
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 8p-1la so nguyen to . chung minh 8n+1 la hop so
cho P la so nguyen to lon hon e
a)chung to rang P co dang 6k+1hoac 6k+3
b)biet 8P+1va P deu la so nguyen to(Plon hon 3).Hoi P+100 ;a so nguyen to hay hop so
