Vay (6n+42) chia het cho 6n
Ma 6n chia het cho 6n
Nen 6n € Ư (42)
Ma Ư (42)={1;2;3;6;7;14;21;42)
Vi 6,42 cha het cho 6
Nen 6n€ {6,42)
=> n=1 hoac n=7
Bai1 a,cho n thuoc N. Chung minh rang 6n+5 va 4n+3 la 2 so nguyen to cung nhau
b, tim so nguyen x sao cho x+2016 la so nguyen duong nho nhat
voi n so tu nhien thoa man 6n+1 va 7n-1 la hai so tu nhien khong nguyen to cung nhau thi uoc chung lon nhat cua 6n+1 va 7n-1 la bao nhieu
cho A=6*n+42 phần 6n với n thuộc Z và N khác 0. tim tat ca cac so nguyen N sao cho Alà số nguyên
tim cac gia tri nguyen cua n de phan so 6n-3 / 3n +1 co gia tri la so nguyen
chung to rang hai so 3n+4 va n+1 la hai so nguyen to cung nhau voi n la so tu nhien khac 0
cho B=n/n-3(n thuoc Z , n khac 3)
tim tat ca cac gia tri nguyen cua n de B la so nguyen
CHo C= 3n+5.n+7(n thuoc Z, N khac -7)
tim tat ca cac gia tri nguyen cua n de C la so nguyen
tim so nguyen n sao cho 6n+1 la boi cua 3n-1
cho a va b la cac so tu nhien khac 0 sao cho trong 4 cau sau a+1 chia het cho b . a=2b+5. a+b chia het cho 3 . a+7b la so nguyen to co 3 cau dung 1 cau sai .tim a,b
bai 1:tim so nguyen x sao cho gia cua cac phan so la so nguyen
a)x+3/x-2
b)x2+3x-2/x+2
chu y:dau / la dau chia trong phan so
bai 2:cho A=2n+1/n-2 voi n la so nguyen
a)tim n de a la phan so
b)tim n de A nguyen
c)tinh gia tri cua A biet:n=2;1;-2;-1
giup minh voi minh dang can.Ai dung minh tick cho
