The value of a is 9, the correct option is B.
Given
Hank’s teacher asked him to verify that the product (y−3)(y2+3y+9), is a difference of cubes.
<h3>Quadratic equation;</h3>
The equation which has the highest degree is 2 is called quadratic equation;
![\rm ax^2+bx+c=0](https://tex.z-dn.net/?f=%5Crm%20ax%5E2%2Bbx%2Bc%3D0)
Where a, b, and c are the constants.
The given polynomial is;
![\rm (y-3)(y^2+3y+9)](https://tex.z-dn.net/?f=%5Crm%20%20%28y-3%29%28y%5E2%2B3y%2B9%29)
On multiplying the terms;
![\rm (y-3)(y^2+3y+9)\\\\y(y^2+3y+9)-3(y^2+3y+9)\\\\y^3+3y^2+9y-3y^2-9y-27\\\\](https://tex.z-dn.net/?f=%5Crm%20%20%28y-3%29%28y%5E2%2B3y%2B9%29%5C%5C%5C%5Cy%28y%5E2%2B3y%2B9%29-3%28y%5E2%2B3y%2B9%29%5C%5C%5C%5Cy%5E3%2B3y%5E2%2B9y-3y%5E2-9y-27%5C%5C%5C%5C)
On comparing;
![\rm ay = 9y\\\\a=9](https://tex.z-dn.net/?f=%5Crm%20ay%20%3D%209y%5C%5C%5C%5Ca%3D9)
Hence, the value of a is 9.
To know more about polynomial click the link is given below.
brainly.com/question/6169816