1. The problem statement, all variables and given/known data Using Ohm's and Kirchoff's Rules find the unknown resistance Rx 2. Relevant equations V = IR Sum of currents at a node is zero Sum of voltages around a loop is zero 3. The attempt at a solution For the 2 ohm resistor I found the voltage to be 4V by the formula V = IR or V = 2A * 2ohm = 4 V Therefore for the Rx resistor the voltage must also be 4 V as is it connected to the 2 ohm resistor in parallel. The 4 and the 8 ohm resistors on top are connected in parallel and therefore must have the same voltage. 12 V - 8 V on the bottom two resistors gives 4 V for them which means that the voltage through each of the top resistors must be 2 V. Knowing this I then took Kirchoff's Current law at the nodes. Node 2 (Right) 2V/ 8 ohm = 0.25 A (going in to the node) - 0.25 A + 2A = -1.75 A (going into the node) Node 1 (Left) -.5 A (into the node) + 1.75 A (going out of the node) = 1.25 A (going out of the node) I then used ohm's law to find the resistance x by V = IR --> R = V/I or 4V/ 1.25 A = 3.2 ohms which is wrong. I thank you in advance for your help.