For example, with something like Soul Foundry, i get to imprint two cards if i want (since there is a may), but how mucho should i pay to activate the ability? Should i choose one creature, pay its cost and get a token, do i pay one (wichever i want?) and get two tokens, do i pay the cost of the two and get two tokens, or if a imprint two cards i can't activate to make tokesn?
For another example, does Semblance Anvil let me exile two cards so i can get reduced cost on extra different card types (i know they are not accumulative)?
Well, thanks in advance and sorry for my english, it's not my first language.
Well, the easy one first. Semblance Anvil, with 2 cards exiled with it, will mean that anything cast that shares a type with *either* exiled card will have its cost reduced.
Now Soul Foundry. Because you have two cards exiled with it, the {X} in the cost is the sum of the CMC of both exiled cards. So, if you exile something with CMC 2 and another with CMC 3, the cost to activate it is {5}. When you do activate it though, you get a token of both cards (whether you want both or not) so you still get use out of both in exile; it just costs a little more.
FYI
The two last rulings under Yarok itself answer both questions (although it may not be as obvious as WizardMN's explaination):
If a triggered ability is linked to a second ability, (…) the second ability (…) refers to all cards exiled by instances of the triggered ability.
and
In some cases involving linked abilities, an ability requires information about “the exiled card.” When this happens, (…) the value of X in the activation cost (…) is the sum of the two cards’ converted mana costs. As the ability resolves, you create copies of both cards (…)
My question is, how does Yarok, the Desecrated work with things with Imprint?
For example, with something like Soul Foundry, i get to imprint two cards if i want (since there is a may), but how mucho should i pay to activate the ability? Should i choose one creature, pay its cost and get a token, do i pay one (wichever i want?) and get two tokens, do i pay the cost of the two and get two tokens, or if a imprint two cards i can't activate to make tokesn?
For another example, does Semblance Anvil let me exile two cards so i can get reduced cost on extra different card types (i know they are not accumulative)?
Well, thanks in advance and sorry for my english, it's not my first language.
Now Soul Foundry. Because you have two cards exiled with it, the {X} in the cost is the sum of the CMC of both exiled cards. So, if you exile something with CMC 2 and another with CMC 3, the cost to activate it is {5}. When you do activate it though, you get a token of both cards (whether you want both or not) so you still get use out of both in exile; it just costs a little more.
The two last rulings under Yarok itself answer both questions (although it may not be as obvious as WizardMN's explaination):
and
In some cases involving linked abilities, an ability requires information about “the exiled card.” When this happens, (…) the value of X in the activation cost (…) is the sum of the two cards’ converted mana costs. As the ability resolves, you create copies of both cards (…)
This situation is covered by rule 607.3.
RULES OF MAGIC :
http://magic.wizards.com/en/game-info/gameplay/rules-and-formats/rules