Respuesta :

AL2006

-- On the upper path, the 3 and the 4 are in series, so they look like 7 ohms.

-- On the lower path, the 5 and the 6 are in series, so they look like 11 ohms.

-- Now you have 7 ohms in parallel with 11 ohms. Can you do that ?

It's 4.28 ohms.