(7n+10)/(5n+7)=[(5n+7)+(2n+3)]/(5n+7)=
=(5n+7)/(5n+7) +(2n+3)/(5n+7)=1+ (2n+3)/(5n+7)
Demonstram ca (7n+10)/(5n+7) are o parte fractionara (subunitara...).
Adica (2n+3)/(5n+7)<1
2n+3<5n+7
3n>-4, adevarat deoarece n€N
Deci (2n+3)/(5n+7)<1
Rezulta ca (7n+10)/(5n+7) are o parte intreaga, ''1'', si o parte fractionara,
(2n+3)/(5n+7)<1, deci (7n+10)/(5n+7) este ireductibila.