Visions of Dominance

To determine the total cost of a spell, start with the mana cost or alternative cost (such as a flashback cost) you're paying, add any cost increases, then apply any cost reductions. The mana value of the spell is determined only by its mana cost, no matter what the total cost to cast the spell was.

A spell cast using flashback will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way.

If a card with flashback is put into your graveyard during your turn, you can cast it if it's legal to do so before any other player can take any actions.

If your commander is under the control of another player as you cast Visions of Dominance using its flashback ability, that commander's mana value can be used to determine the value of X.

You can cast a spell using flashback even if it was somehow put into your graveyard without having been cast.