wotc
If a card in a player's hand has {X} in its mana cost, X is considered to be 0.
If a card in a player's hand has {X} in its mana cost, X is considered to be 0.
If a spell has {X} in its mana cost, include the value chosen for that X when determining the mana value of that spell, even if it was cast for an alternative cost and no mana was spent on X.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Greg Staples
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