Răspuns:
a
4n+2/13 ---- subuitara => 4n+2<13 ; 4n<11 n<11/4 => n=0; 1; 2.
b.
7n+2/4n+11 --- echiunitara => 7n+2=4n+11 ;
7n-4n=11-2 ; 3n=9; => n= 9/3=3
3.
n+1/7 subunit => n+1<7; n<6.
