{1/x+1/y=5/6
{1/y+1/z=1/2
{1/x+1/z=2/3
{сложим
{2/x+2/y+2/z=5/6+1/2+2/3
{2(1/x+1/y+1/z)=2
{1/x+1/y+1/z=1
за 1 час
{1/x+1/y=5/6
{1/y+1/z=1/2
{1/x+1/z=2/3
{сложим
{2/x+2/y+2/z=5/6+1/2+2/3
{2(1/x+1/y+1/z)=2
{1/x+1/y+1/z=1
за 1 час