Answer: a= 16
Explanation:
We have the following expression:
![(y-4)(y^2 +4y +16)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/crk42v5ramcor5ewpxk1aseoka2sar6xpf.png)
To find the value of the coefficient "a" you must use the distributive property to multiply the expression:
![(y-4)(y^2 +4y +16)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/crk42v5ramcor5ewpxk1aseoka2sar6xpf.png)
until you transform it to the form:
![y^3 +4y^2 +ay -4y^2 -ay-64](https://img.qammunity.org/2020/formulas/mathematics/middle-school/18hlfm21kfh3yqxrxwqy83ojlr8czjg000.png)
Then we have
![(y-4)(y^2 +4y +16)\\\\(y^3 +4y^2 +16y -4y^2 -16y-64)\\\\](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ggcxz9u3t47qzzq69xiauhztskzeaok7nl.png)
Therefore the value of a in the polynomial is 16