Respuesta :

sqdancefan

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Answer:

  27y^12 cubic feet

Step-by-step explanation:

Put the given side length into the formula and simplify according to the rules of exponents.

  V = (3y^4)^3 = 3^3·y^(4·3) = 27y^12

The volume of the vault is 27y^12 cubic feet.