Question

giúp e vs ạ

Answer 1

2: ĐKXĐ: n<>1/3

Để \(\dfrac{12}{3n-1}\in Z\) thì \(12⋮3n-1\)

=>\(3n-1\in\left\{1;-1;2;-2;3;-3;4;-4;6;-6;12;-12\right\}\)

=>\(3n\in\left\{2;0;3;-1;4;-2;5;-3;7;-5;13;-11\right\}\)

=>\(n\in\left\{\dfrac{2}{3};0;1;-\dfrac{1}{3};\dfrac{4}{3};-\dfrac{2}{3};\dfrac{5}{3};-1;\dfrac{7}{3};-\dfrac{5}{3};\dfrac{13}{3};-\dfrac{11}{3}\right\}\)

mà n nguyên

nên \(n\in\left\{0;1;-1\right\}\)