How Do You Apply Kirchhoff's Rules to Solve for Currents in a Complex Circuit?

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Homework Statement


Using Kirchhoff's rules, find the currents I1, I2, and I3 in the circuit shown where R1 = 8.0 ohms, R2 = 9.0 ohms, and R3 = 5.0 ohms.
Circuit schematic with a 10 V battery across the top branch, resistors R1 on the left branch, R2 in the middle horizontal branch and R3 along the bottom, with currents I1, I2 and I3 marked by arrows.

Homework Equations


Loop law, Junction law

The Attempt at a Solution


I know how to work the formulas, but the picture is really confusing. The directions of the currents don't make any sense. I have arrows going away from both the positive and negative terminal and I can't figure out how to set up the equations with the arrows like that.
 
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  • Circuit schematic with a 10 V battery on the top branch, resistor R1 on the left branch, resistor R2 on the middle branch with current I1 pointing right, resistor R3 on the bottom branch, and currents I2 and I3 shown on the right side.
    ae21-9.gif
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The first thing you need to do is choose a direction which you will take as positive, either clockwise or anti-clockwise. Once you have chosen your convention make sure you stick to it. Then just start applying Kirchoff's laws to the loops and junctions taking care to stick to the convention you defined at the start.