For the polynomial negative 2 m squared n cubed plus 2 m to the ? th power n cubed plus 7 n squared minus 6 m to the 4th power to be a binomial with a degree of 4 after it has been fully simplified, which must be the missing exponent on the m in the second term?

To leave a binomial, the first two terms must be like terms so they can combine. Setting the missing exponent to 2 makes them −2m²n³ and +2m²n³, which cancel. The remaining terms are 7n² and −6m⁴, a binomial whose greatest degree is 4, so the missing exponent is 2 (choice D).

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