I'm interested in the equation

x |
+ | y |
= |

x |
= | y |
= |

x | = | + | k; | ||

y | = | + | k; | (where k∈Z) |

*x* and any *y* would work.

I'm interested in the congruence

x |
≡ | (mod |

*x*.

x | ≡ | (mod |

I'm interested in the simultaneous congruences

x | ≡ | (mod | |

x | ≡ | (mod |

x | ≡ | (mod |