👤

Determinati elementele multimii:
A={ [tex]\frac{}{xy} [/tex] ∈N |[tex]\frac{}{xy}=(x+y)^{2}-2[/tex]}


Răspuns :

Cele doua cifre pot lua valorile:

[tex]x\in \{1,2,3...,9\}\\ \\ y\in \{0,1,2,3,...,9\}[/tex]

Iei si verifici toate posibilitatile, de ex.:

[tex]x=1\ \ y=0\ \ \ \Rightarrow \ \ \ 10=(1+0)^2-2\ \ \ \ (Fals)\\ \\ x=1\ \ y=1\ \ \ \Rightarrow \ \ \ 11=(1+1)^2-2\ \ \ \ (Fals)\\ \\ .........etc.........[/tex]

La final, bagi in multimea ceruta acele numere care au verificat relatia.