Jodah, Archmage Eternal

• WWizards of the Coast2018-04-27
  Official Ruling
  If you apply Jodah's alternative cost to a spell with in its mana cost, X is 0.
• WWizards of the Coast2018-04-27
  Official Ruling
  If you cast a spell for which mana may be spent as though it were mana of any color, you may cast it for Jodah's alternative cost and still spend mana as though it were mana of any color.
• WWizards of the Coast2018-04-27
  Official Ruling
  Jodah's ability is an alternative cost to cast a spell. You can't combine this with other alternative costs, such as flashback. You can pay additional costs, such as kicker, in addition to this alternative cost.

Rulings via Scryfall