Which expression is equivalent to (4 + 7i)(3 + 4i)?

Multiply each term: (4 + 7i)(3 + 4i) = 12 + 16i + 21i + 28i². Since i² = −1, 28i² = −28, so the real part is 12 − 28 = −16 and the imaginary part is 16i + 21i = 37i. The equivalent expression is −16 + 37i, choice A.

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