What is the sum of the polynomials? open paren 7 x cubed minus 4 x squared close paren plus open paren 2 x cubed minus 4 x squared close paren

Combine like terms: the cubic terms give 7x³ + 2x³ = 9x³, and the squared terms give −4x² − 4x² = −8x². The sum is 9x³ − 8x², choice D.

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