@Override
public Set solve() throws EquationSolveException {
rules = new RuleMachine(this);
rules.addRule(new Fraction());
rules.addRule(new DistributiveLaw());
rules.addRule(new AssociativeLaw());
rules.addRule(new VariableOnBothSides());
rules.addRule(new AxpBeC());
rules.addRule(new AxeB());