State Kirchhoff's rules . Apply Kirchhoff's rules to the loops ACBPA and ACBQA to write the expressions for the currents `I_(1) , I_(2)` and `I_(3)` in the network .

Explanation

**Step-by-step Solution:**

1. **State Kirchhoff's Rules:**
- **Kirchhoff's Current Law (KCL):** The sum of currents entering a junction is equal to the sum of currents leaving the junction. Mathematically, it can be expressed as:
\[ I_{in} = I_{out} \]
- **Kirchhoff's Voltage Law (KVL):** The sum of the electrical potential differences (voltage) around any closed circuit loop is zero. This can be expressed as:
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