Question

Determinați perechile de numere naturale (a,b) ştiind că are loc egalitatea (a-1)•(b+1)=6

Answer 1

(a-1)·(b+1)=6
6=1·6
a-1=1⇒a=2;
b+1=6⇒b=5;
6=2·3
a-1=2⇒a=3;
b+1=3⇒b=2;
6=3·2
a-1=3⇒a=4;
b+1=2⇒b=1;
6=6·1
a-1=6⇒a=7;
b+1=1⇒b=0;
In concluzie (a;b)∈{(2;5),(3;2),(4;1),(7;0)}