tim k sao cho 3^(6n-1)-k.3^(3n-2)+1 chia het cho 7 voi moi so nguyen duong n
tim tat ca cac so nguyen duong n sao cho:2^n-1 chia het cho 7
TIM N LA SO NGUYEN SAO CHO
a , 3n +11 chia het cho n
b , 2n - 7 chia het cho n+ 2
c , n2 + 2n + 10 chia het cho n+ 1
tim tat ca cac so nguyen n sao cho n^2+4 chia het n+2
bai 1 tim cac stn x y z sao cho x+y+z=xyz
bai 2cmr neu m^2+mn+n^2chia het cho 9 voi m ,n la cac stn thi m,n chia het cho 3
bai 3 tim stn n nho nhat de cac phan so sau toi gian
7/n+9.8/n+10,...,31/n+33
bai 4chung to rang phan so m^3+2m/m^4+3m^2 +1 toi gian
bai 5 a,cmr khong ton tai so chinh phuong nao co dang abab
b,cho 51 so nguyen duong khong vuot qua 100 cmr ton tai 2 so trong 51 so noi tren ma 1 so chia het cho so con lai
c,tim cac so co 3 chu so sao cho hieu cua so ay va gom 3 chu so ay viet theo thu tu nguoc lai la mot so chinh phuong
bai 6cmr A=2x(x+y-1)+y^2+1 luon nhan gia tri khong am voi moi x,y
bai 7 tim hai so nguyen duong sao cho tong ,hieu thuong (so lon chia cho so nho )cua chung cong lai duoc 38
bai 8 cho ba so a,b,c thoa man a/2009=b/2010=c/2011
tinh gia tri cua bieu thuc M=4(a-b)(b-c)-(c-a)^2
tim cac so nguyen n sao cho 2n-3 chia het cho n+1
chung minh rang voi moi so nguyen duong n thi
10n + 18n -1 chia het cho 27
chung minh rang : voi moi so nguyen duong n thi :3n+2 -2n+2 +3n -2n chia het cho 10