A circuit is constructed with six resistors and two batteries as shown. The battery voltages are V1 =
18 V and V2 = 12 V. The positive terminals are indicated with a + sign, The values for the resistors are: R1 = R5 = 44 Ω, R2 = R6 = 134 Ω R3 = 113 Ω, and R4 = 83 Ω. The positive directions for the currents I1, I2 and I3 are indicated by the directions of the arrows.
What is V(a) - V(b), the potential difference between the points a and b?