Step 1: Identify the circuit components and their values.
The circuit consists of three parallel branches. Each branch contains a voltage source and a resistor in series.
• Branch 1 (Top): Resistor R1=3Ω, Voltage source E1=6V. The positive terminal of E1 is on the left.
• Branch 2 (Middle): Resistor R3=3Ω, Voltage source E2=9V (assuming the red mark indicates the value). The positive terminal of E2 is on the left.
• Branch 3 (Bottom): Resistor R2=3Ω, Voltage source $E