Given the circuit I have to find the source voltage S and unknown resistance R3. It is stated that the power dissipated in R6 = 3 ohm is 0.75W. How should I attempt to solve the source voltage where there are two unknown variables?
Edit: Combining series resistors and trying mesh analysis:
14I1-2I2 = S ...(i)
-2I1+18I2-4I3 = 0 ...(ii)
P=(I^2)*R , So, I3=0.5A