[tex]x = numarul \\ y = cealalt \: numar \\ x = 3 \times y[/tex]
[tex]x + y = 40[/tex]
inlocuim in formula:
[tex]3 \times y + y = 40 \\ 4y = 40 \\ y = 40 \div 4 \\ y = 10 \\ x = 3 \times y \\ x = 3 \times 10 \\ x = 30[/tex]
verificare:
30+10=40
