Ta có:
3n + 9 = 3n + 3 + 6 = 3(n + 1) + 6
Để (3n + 9) ⋮ (n + 1) thì 6 ⋮ (n + 1)
⇒ n + 1 ∈ Ư(6) = {-6; -3; -2; -1; 1; 2; 3; 6}
⇒ n ∈ {-7; -4; -3; -2; 0; 1; 2; 5}
(Nếu tìm n là số tự nhiên thì n ∈ {0; 1; 2; 5})
cho n thuoc N tim UCLN cua
a) 2n+1 va 3n+1
b)20n+1va 15n+2
chung to rang 5 khong phai la u(3n +1va 5n+2) (n€N)
chung to rang hai so n+1va 3n+4(n e N)la hai so nguyen to cung nhau(cho minh cach giai nhe)
bai 1:tim x
a) (x+1/5)2+17/25=26/25
b)-1va 5/27-(3x-7/9)3=-24/27
bai 2:cho A=n+2/n-5 (n thuoc Z ;n khac 5).Tim x de A thuoc Z
Tim UCLN cua n-1va 9n+4(n thuoc N)
Giup minh giai nhe
tim abc nho nhat sao cho abc=n^2-1va abc=n^2-4n+4
tim tat ca cac stn co 3cs abc sao cho abc =n^2-1va cba=(n-2)^2
chung to 2 so sau la 2 so nguyen to cung nhau
a,2n+3 va n+2
b,3n+1va 2n+1
c,n+10 va n+11
tim n de
3n+9/n-4 thuộc Z
