Final answer:
Kirchhoff's junction rule at point A states that I₁ = I₂ + I₃.
Step-by-step explanation:
When applying Kirchhoff's junction rule at point A, we can use the equation: I₁ = I₂ + I₃. This rule states that the sum of all currents entering a junction must equal the sum of all currents leaving the junction. In this case, we have three currents: I₁, I₂, and I₃. The equation shows that the current flowing into point A (I₁) is equal to the sum of the currents flowing out of point A (I₂ and I₃).