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Enegica1982
a fost răspuns

A={x∈N divide cu 2x divide 5} B={x∈N divide x-2 divide x +9} Afla: A=? ; B=? ; ; A∪B ; A∩B ; A-B ; B-A.

Răspuns :

Albatran
A={x|  2x|5} 2x=1, x=1/2∉N
   2x=5, x=5/2∉N
A=∅
x-2|x+9
(x+9)/(x-2)∈N
(x-2+11)/(x-2) ∈N
(x-2)/(x-2) +11/(x-2)∈N
1+11/(x-2)∈n
 x-2∈D11
x-2=1; x=3
x-2=11 x=13
deci A=∅; B={3;13}
A∪B=B
A∩B=∅
A\B=∅
B\A=B

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