Which are perfect cubes? Check all that apply.

A monomial is a perfect cube when its numerical coefficient is a perfect cube and each variable’s exponent is divisible by 3. Here, 64 = 4³, 8x³ = (2x)³, and 125x⁹ = (5x³)³. The other choices fail one of these tests: their coefficients or exponents are not perfect-cube factors.

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