For the polynomial –2m2n3 + 2m?n3 + 7n2 – 6m4 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?

The first two terms combine only if they have the same powers of both variables. Setting the missing exponent to 2 makes them −2m²n³ + 2m²n³, which cancel. The remaining polynomial is 7n² − 6m⁴, a binomial whose degree is 4, so the missing exponent must be 2.

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