Mathematics

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Across
  1. 2. (3,5,24),(4,5,27),(3,9,36),(7,3,?)
  2. 3. 303³+404³+505³=X³,X=?
  3. 5. 3X+14=50,X=?
Down
  1. 1. 4⁵
  2. 4. 28×28-(28+28)÷28