What's my next hardest?

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Across
  1. 3. "It's a-me, _____!"
  2. 4. Capital of France
  3. 5. The most famous Batman villain
  4. 7. 57 according to the list which people grind excessively
  5. 8. 2(6x-3) = 90 . Solve for x
Down
  1. 1. Solid, _____, Gas
  2. 2. Creator of Sedulous
  3. 6. ___ are red, violets are blue