Final answer:
To find the equation at point A, apply Kirchhoff's junction rule. Apply Kirchhoff's loop rule to find the equations for the upper and lower loops. Use the given values of resistors and voltages to calculate the unknowns.
Step-by-step explanation:
In this circuit, labeled as Figure 10.26(a), start by applying Kirchhoff's junction rule at point A to find the equation. The junction rule states that the sum of currents flowing into a junction is equal to the sum of currents flowing out. By labeling the currents and applying the rule, you can find the equation for point A.
To find the equations obtained by applying Kirchhoff's loop rule in the upper and lower loops, you need to apply the loop rule which states that the sum of potential differences around a closed loop is equal to zero. By analyzing the upper and lower loops and applying the loop rule, you can find the equations for each loop.
To calculate the values of /1, /2, and 13, you need to use the given values for resistors (R₁, R₂, R₃, and r₁), as well as the given values for voltages (E₁ and E₂). Plug these values into the appropriate equations and solve for the unknowns.