Question

$\frac{u-2}{2} =\frac{u-6}{6}$

Answer 1

$\frac{u-2}{2}=\frac{u-6}{6}\\\\6*(u-2)=2*(u-6)\\\\6u-12=2u-12\\\\6u-2u=12-12\\\\4u=0\\\\u=0:4\\\\u=0$

Проверка:

$\frac{0-2}{2}=\frac{0-6}{6}\\\\\frac{-2}{2}=\frac{-6}{6}\\\\-1=-1$

Ответ:  $u=0$