Question

Daca d divide (..........) si d divide (2n+4), atunci d divide(2n+7)-(2n+4), adica d | 3 deci b apartine {........}
Repedeee va rog!

Answer 1

daca d | (2n+7) si d | (2n+4) atunci d | (2n+7)-(2n+4),  vezi proprietatile divizibilitatii
d | (2n+7) ⇒ d | (2n+4+3) ⇒ d | (2n+4) +3 ⇒ d | 3 ⇒ d={1,3}