Nếu n chia hết cho 5
=> UCLN( n+5;5) =5
Nếu n không chia hết cho 5
=> UCLN( n+5;5) =1
Nếu n chia hết cho 5
=> UCLN( n+5;5) =5
Nếu n không chia hết cho 5
=> UCLN( n+5;5) =1
1,tim 2 so tu nhien biet tong chung = 66 UCLN=6 co 1 so chia het cho 5
2,tim 2 so tu nhien biet hieu chung = 84 UCLN = 12
3,tim 2 so tu nhien biet tich = 864 UCLN=6
4,cho 3n+1 va 5n+4 la 2 so nguyen to cung nhau tim UCLN cua 3n+1 va 5n+4
5,cho a=123456789;b=987654321 . Tim UCLN cua a va b
Cau 1: Co tat ca bao nhieu so co 3 chu so ma trong moi so co duy nhat 1 chu so 5.
Cau 2: Biet rang 3n+1 va 5n+4 (n thuoc N) la hai so khong nguyen to cung nhau. Khi do UCLN cua 3n+1 va 5n+4 la bao nhieu.
Cau 3: Tim cap (x;y) nguyen am thoa man:xy+3x+2y+6=0 va lxl+lyl=5.
Tim hai so nguyen duong x,y biet x/y = -21/-91 va UCLN(x,y) =5
tim ucln cua 24 va 70
tim ucln cua 81 va 54
tim ucln cua 128 va 112
tim ucln cua 108 va 160
tim hai so nguyen to co tich bang 300 va ucln cua chung bang 5
Tim x
a, tim cac so nguyen x,y sao cho y/3 - 1/x = 1/3
b,tim cac so a va b biet a - b =5 va UCLN (a,b)/BCNN (a,b) =1/6
Luu y a/b tua la a phan b
Tim hai so a va b biet tong cua BCNN va UCLN cua chung la 15.
Tim hai so tu nhien a va b biet tich cua chung l 216 va UCLN cua chung la 6
Tim a , b \(\in\)N biet a + b = 128 va UCLN ( a , b ) = 16
Goi y : a) a = 6. m b = 6.n
(m,n)=1
.GIUP MINH NHA
Bai 1: a)Tim so tu nhien a biet 1960va2002 chia cho a cung co so du la 28
b)Tim 2 sop tu nhien a va b , biet :BCNN(a,b)=300;UCLN(a,b)=15 va a+15=b
Bai 2:a)Tong sau la binh phuong so nao ?
S=1+3+5+7+...+199
b) Cho so ab va so ababab
1)chung to ababab la boi cua ab
2)So 3 va 10101 co phai la uoc cua ababab khong , vi sao?
Bai 3
a)Hay viet them dang sau so 664 ba chu so de nhan duoc sdo co 6 chu so chia het cho 5,9,11
b)Tim so nguyen x thuoc Z biet rang :
(x^2-1)(x^2-4)<0
Bai 4 :tim so nguyen x va y biet: xy-x+2y=3