What is the sum of the polynomials?(7x3 – 4x2) + (2x3 – 4x2)

Combine like terms by adding the coefficients of matching powers of x: 7x³ + 2x³ = 9x³, and −4x² + (−4x²) = −8x². The sum is 9x³ − 8x², which is choice D.

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