If you would like to find the value of a in the polynomial, you can do this using the following steps:
(y - 4)(y^2 + 4y + 16) = y^3 + 4y^2 + 16y - 4y^2 - 16y - 64 = y^3 + 4y^2 + ay - 4y^2 - ay - 64
a = 16
The correct result would be 16.
Answer: ![t\in [\dfrac{1}{4},2]](https://tex.z-dn.net/?f=t%5Cin%20%5B%5Cdfrac%7B1%7D%7B4%7D%2C2%5D)
Step-by-step explanation:
Given
Inequality is 
Taking variables one side

Using wavy curve method
![t\in [\dfrac{1}{4},2]](https://tex.z-dn.net/?f=t%5Cin%20%5B%5Cdfrac%7B1%7D%7B4%7D%2C2%5D)
-12x^6 - 60x^5-75x^4.......GCF = 3x^4
3x^4(-4x^2 - 20x - 25)
3x^4(-2x - 5)(2x + 5) <==