Factor x3y6 + 27z42.

Rewrite the expression as a sum of cubes: x³y⁶ = (xy²)³ and 27z⁴² = (3z¹⁴)³. Using a³ + b³ = (a + b)(a² − ab + b²), with a = xy² and b = 3z¹⁴, gives (xy² + 3z¹⁴)(x²y⁴ − 3xy²z¹⁴ + 9z²⁸). This is choice D.

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