Question

$y=7x+\frac{2}{x}$
nayti naimenshi znacheniya funksiya

Answer 1

 
          $y'=7 - \frac{2}{x^2} \\ y'= 0 \\ x=\sqrt{\frac{2}{7}} \\ f(\sqrt{\frac{2}{7}}) = 2 \sqrt{14}$  
       $minimal \ 2\sqrt{14}$