Question

Câu 5: (1,0 điểm): Tìm số nguyên n biết rằng n – 4 chia hết cho n -1

Giúp mik với :333

 

Answer 1

\(\left(n-4\right)⋮\left(n-1\right)\Rightarrow\left(n-1-3\right)⋮\left(n-1\right)\)

\(Mà\left(n-1\right)⋮\left(n-1\right)\Rightarrow-3⋮\left(n-1\right)\Rightarrow n-1\inƯ\left(-3\right)=\left\{\pm1;\pm3\right\}\Rightarrow n\in\left\{-2;0;2;4\right\}\)

 

Answer 2

<=> n-1ϵ(1,-1,3,-3)

Answer 3

\(\dfrac{n-4}{n-1}=\dfrac{n-1}{n-1}-\dfrac{4}{n-1}\)

Nhận xét:

\(\left(n-1\right)⋮\left(n-1\right)\\ \left(n-4\right)⋮\left(n-1\right)\\ \Rightarrow4⋮\left(n-1\right)\\ Hay.\left(n-1\right)\inƯ_{\left(4\right)}=\left\{-4;-2;-1;1;2;4\right\}\\ \Rightarrow n\in\left\{-3;-1;0;2;3;5\right\}\)

Answer 4

(n−4)⋮(n−1)⇒(n−1−3)⋮(n−1)(n−4)⋮(n−1)⇒(n−1−3)⋮(n−1)

Mà(n−1)⋮(n−1)⇒−3⋮(n−1)⇒n−1∈Ư(−3)={±1;±3}⇒n

∈{−2;0;2;4}

Answer 5

(n−4)⋮(n−1)⇒(n−1−3)⋮(n−1)(n−4)⋮(n−1)⇒(n−1−3)⋮(n−1)

Mà(n−1)⋮(n−1)⇒−3⋮(n−1)⇒n−1∈Ư(−3)={±1;±3}⇒n

 

∈{−2;0;2;4}