Answer:
R + 6 ohms
Step-by-step explanation:
The current is the same in all three resistors
i = 2 amps
The problem is that the total voltage is unknown.
R = r
R1 =3 ohms
R2 = 3 ohms
The voltage drop is E = I*R
I = 2 amps
R1 = 3 ohms
R1 = 3 ohms
E = 3*2 = 6 volts
The second 3 ohm resistor also has 6 volts across it.
The total is 12 volts so far. But we know nothing more on how to solve for R.
All you can say is that the total resistance = R + 6 ohms