What is the product of a+3 and −2a2+15a+6b2?

Distribute both terms in a + 3 across the polynomial: a(−2a² + 15a + 6b²) = −2a³ + 15a² + 6ab², and 3(−2a² + 15a + 6b²) = −6a² + 45a + 18b². Combine like terms, so 15a² − 6a² = 9a²; the result is −2a³ + 9a² + 45a + 6ab² + 18b², choice C.

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