Chandra down -7 + strive

[redwolv]

 {Chandra, Pyromaster}
  {Rouse the Mob}
So if you -7 chandra and get rouse the mob can you only use each copy on a single target or can you "pay" the strive and pick more targets? According to a ruling you can "pay" for stuff like kicker, which is an alternative mana cost. But another ruling says if the cost has X the X is counted as 0. So i was wondering how strive would work as it is not an alternative cost(like kicker) so much as a cost increased to ones liking(like X)

[Remillo]

Strive is an ability that adds additional costs.  Unlike Overload or Flashback, it's not an Alternate cost.

If you cast a spell with Strive off of Chandra (We'll say {Desperate Stand}), you choose any number of target creatures.  Then, you calculate the cost.  Chandra says to cast it without paying its mana cost, so the {R}{W} in the top corner is paid for.  Then Strive says, "Well, how many extra targets do you have?  Add {R}{W} for each one".  So if you target three creatures, it'll cost {R}{R}{W}{W}, instead of {R}{R}{R}{W}{W}{W} (without the 'Without paying its mana cost')

[Nymuera]

Very nice!! On a side note, why is strive not in the rules? Do the rules need to be updated?

[Remillo]

Very nice!! On a side note, why is strive not in the rules? Do the rules need to be updated?

The comp rules that I find on Wizards website also doesn't seem to have been updated since November.  Though, Strive May not appear in the comp rules, anyway, since it's an ability word that doesn't actually have an ability, like landfall or chroma.  It's just there to flag to players 'it has this kind of ability'.