b) A=\(\dfrac{n+1}{2n-1}\) là số nguyên
A= \(n+1⋮2n-1\)
A= \(2\left(n+1\right)⋮2n-1\)
A= \(2n+2⋮2n-1\)
A= \(2n-1⋮2n-1\)
A= \(\left(2n+2\right)-\left(2n-1\right)⋮2n-1\)
A= \(3⋮2n-1\)
=> \(2n-1\inƯ\left(3\right)\)={ \(\pm\)1;\(\pm\)3}
=> n = { 1; 0; 2;-1 }