To make a three phase generator you have to place a certain number of magnets on your stator and armature, all with proper spacing. Electromagnetism is as complex as dealing with waves and water, so you need to know how to control the field through your design.
Tutorial 20: Solving Systems of Linear Equations in Three Variables will cover systems that have three equations and three unknowns. We will look at solving them three different ways: graphing, substitution method and elimination method. This will lead us into solving word problems with systems, which will be shown in Tutorial 21: Systems of Linear Equations and Problem Solving.
Elimination is also the best method to use if all of the variables have a coefficient other than 1. I hope this gives you some idea about which method you should use. All three methods will give the same solution. Also, you should always check your answer in both equations to make sure it is correct.