Determinați numerele naturale de forma 12x, 5x3, xy,
care se divid cu 4.
[tex]\it \overline{12x}\ \vdots \ 4 \Rightarrow \overline{2x}\ \vdots \ 4 \Rightarrow x\in\{0,\ \ 4,\ \ 8\}\\ \\ Numerele\ \ cerute\ \ sunt:\ 120,\ \ 124,\ \ 128[/tex]
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[tex]\it Numerele\ de\ forma\ \overline{53x}\ sunt\ impare,\ pentru\ oricare\ x-cifr\breve a,\\ \\ deci\ nu\ exist\breve a\ nici\ un\ astfel\ de\ num\breve ar\ divizibil\ cu \ 4.[/tex]
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[tex]\it \overline{xy}\ \vdots\ 4 \Rightarrow \overline{xy}\in\{12,\ 16,\ 20,\ 24,\ ...\ ,\ 96\}[/tex]
