[tex]x\to nr. \ de \ banci \\\\\\ x+6 \to nr. \ de \ elevi \\ 2(x-4)+1 \to nr. \ de \ elevi \\\\\\ x+6=2(x-4)+1 \\\\ x+6=2x-8+1 \\\\ x+6=2x-7 \\\\ x-2x=-7-6 \\\\ -x=-13 \\\\ \boxed{x=13 \ (banci)} \\\\ x+6= \\\\ =13+6= \\\\ =\boxed{ 19 \ elevi}[/tex]