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:  $u=0$