[tex]x\to nr. \ elevilor \\\\ \frac{1}{2} \ din \ x= \frac{1}{2}*x \to \frac{x}{2}-mate \\\\ \frac{1}{7} \ din \ x= \frac{1}{7} *x \to \frac{x}{7}-meditau \\\\ \frac{1}{4} \ din \ x= \frac{1}{4}*x\to \frac{x}{4}-studiau \ natura \\\\ \frac{x}{2}^{(14}+ \frac{x}{7}^{(4}+ \frac{x}{4}^{(7}+3^{(28}=x^{(28} \\\\ 14x+4x+7x+84=28x \\\\ 25x+84=28x \\\\ 25x-28x=-84 \\\\ -3x=-84 \ \ \ |:(-3) \\\\ \boxed{x=28 \ elevi}[/tex]
