tim n la stn de p=(x-1)(x^2-x+1) la snt
Tim STN x:
a, 3x+2010 la SNT
b,1!+2!+3!+...+x! la SNT
Tim stn n de n+1 va n-3 la 2 snt cung nhau
\(Giai\)
\(Goi:d=\left(n+1,n-3\right).\)
\(taco:\hept{\begin{cases}n+1⋮d\\n-3⋮d\end{cases}}\Rightarrow\left(n+1\right)-\left(n-3\right)⋮d\Leftrightarrow4⋮d\Rightarrow d\in\left\{1;2;4\right\}\)
\(\left(n+1,n-3\right)=1\Leftrightarrow d=1\Leftrightarrow\orbr{\begin{cases}n+1=2k+1\left(k\inℕ\right)\\n-3=2k+1\left(k\inℕ\right)\end{cases}\Leftrightarrow\orbr{\begin{cases}n=2k\\n=2k+4\end{cases}}}\left(n,chẵn\right)\)
\(Vậy:với,n,chẵn,thì,:\left(n+1,n-3\right)=1\)
tim n la stn de p=(x-1)(x^2-x+1) la 1 so nguyen to
tim x va n de x4 + 24n+2 la snt
Ta có : x4 là số tự nhiên
Nên : 24n + 2 là số tự nhiên
=> 4n + 2 là số tự nhiên
=> 4n + 2 > -1
=> 4n > - 3
=> n > \(-\frac{3}{4}\)
tim x,y thuoc N* sao cho 8x^3+y^3-6xy+1 la SNT
1) tim stn x biet rang (x+4).(23-x)=0
2) tong cac chu stn le tu 1 den 999 la
A = 2/ x-1 .tim dieu kien cua x de A la phan so . tim A khi x = 2 ; x = -3. tim dieu kien cua x de A la so nguyen ( A thuoc Z )
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
a, Cho a,b la cac STN . CTR neu 5a+3b va 13a+8b cung chia het cho 2018 thi a va b cung chia het cho 2018
b, tim cac chu so x, y sao cho 2018xy chia het cho 54
c, tim so nguyen x de ps A=\(\frac{5-x}{x-2}\)la co gia tri la STN