`a)(n+3)/(2n-2) (n in ZZ)`
`=> (n+3) \vdots (2n-2)`
`=>(2n-2+8) \vdots (2n-2)`
`=> (2n+6) \vdots (2n-2)`
`=> (2n-2+8)-(2n-2) \vdots (2n-2)`
`=>8 \vdots (2n-2)`
`=>(2n-2) in Ư(8)={+-1;+-2;+-4;+-8}`
Vậy `n in {-3;-1;0;2;3;5}`
``
`b)12/(3n-1) (n in ZZ)`
`=>12 \vdots (3n-1)`
`=> (3n-1) in Ư (12)={ +- 1 ; +- 2 ; +- 3 ; +- 4 ; +- 6 ; +- 12}`
Vậy `n in {0;-1}`
``
`c)(2n+3)/7 (n in ZZ)`
`=>(2n+3) \vdots 7`
`=>(2n-4) \vdots 7`
`=>n=7k+2 (k in ZZ)`
Vậy `n=7k+2(k in ZZ)`
``
`d)(8n+193)/(4n+3) (n in NN)`
`=>(8n+193) \vdots (4n+3)`
`=>(8n+193) \vdots (8n+6)`
`=>(8n+193)-(8n+6) \vdots (8n+6)`
`=>187 \vdots (8n+6)`
`=>(8n+6) in Ư (187)={1;11;17;187}`
Vậy `n in{156;165;167}`
