cho p la so nguyen to lon hon 3 chung minh rang p^2-1 chia het cho 24
chung minh rang voi moi so nguyen m thi 4m^3 + 9m^2 - 19m - 30 chia het cho 6
Cho 12 so deu la so nguyen to(a1,a2,...,a12), chung minh rang:
(a1-a2)(a3-a4)(a5+a6) chia het cho 1800
cmr neu tong cac lap phuong cua ba so nguyen lien tiep chia het cho 9 thi se co mot so la boi cua 3
Cho f(x)=ax3+bx2+cx+d. CMR neu 6a, 2b, a+b+c va d la cac so nguyen to thi f(x) co gia tri nguyen voi moi so nguyen x
chung minh rang :B=x.y(x^2-y^2).(x^2+y^2)chia het cho 30 (x;y la so nguyen)
chung minh rang voi moi so nguyen duong n thi
10n + 18n -1 chia het cho 27
cac ban cho minh hoi
chung to rang neu a/b<c/d (b>0,d>0) thi a/b<a+c/b+d<c/d
Bai 1: chung minh rang: voi moi so nguyen duong n thi:
\(3^{n+2}-2^{n+2}+3^n-2^n\)chia het cho 10
Bai 2: Chung to rang:
A=75.(4\(^{2004}\)+4\(^{2003}\)+....+4\(^2\)+4+1)+25 la so chia het cho 100
Bai 3: Chung minh rang 3a + 2b :17 [=] 10a +b :17 (a,b thuoc Z)
b, Cho da thuc f(x) =ax\(^2\)+ bx+c 9a,b,c nguyen)
CMR nếu f(x) chia hết cho 3 với mọi giá trị của x thì a,b,c đều chia hết cho 3 ?
Mau giup minh voi
