Răspuns:
[tex]x = nr. \: elevi[/tex]
[tex]x = 4y + 2[/tex]
[tex]x = 7y + 5[/tex]
[tex]x + 2 = 4y + 4[/tex]
[tex]x + 2 = 7y + 7[/tex]
[tex]x + 2 = 4(y + 1)[/tex]
[tex]x + 2 = 7(y + 1)[/tex]
[tex]4 \times 7 = 28[/tex]
[tex]x + 2 = 28[/tex]
[tex]x = 28 - 2[/tex]
[tex]x = 26 \: elevi[/tex]