Question

He product of a + 3 and –2a2 + 15a + 6 is –2a3 + xa2 + 51a + 18. What is the value of x?

Answer 1

9

Explanation:

The contributors to the a² term in the product are ...

... 3×(-2a²) + a(15a) = a²(-6+15) = 9a²