Question

please answer with steps as soon as possible​

Answer 1

$(9m + 7n) ^{2} - (9m - 7n) ^{2} \\ = (9m + 7n + 9m - 7n)(9m + 7n - 9m + 7n) \\ = 18m \times 14n \\ = 252mn$

Answer:

C. 252 mn

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