The greatest common factor of a polynomial is the largest expression that divides all of the terms of the polynomial. In this case, we have:
![2(c+y)^3-14(c+y)^2-6(c+y)^4](https://img.qammunity.org/2023/formulas/mathematics/high-school/w8vr5zliwcyj0h8ezbpkg0hpd1u7w0o5il.png)
First, find the GCF of the coefficients of the terms. The coefficients are 2, 14 and 6, their GCF is 2.
On the other hand, notice that the factor (c+y) is a common factor for all three terms. Find the greatest power of (c+y) that divides all the terms. Since the lowest power of (c+y) in the expression is 2, then, the greatest power of (c+y) that divides all the terms is (c+y)^2.
The GCF of the expression is the product of the GCF of the coefficients and the GCF of the factors with variables.
Then, the GCF of the expression is:
![2(c+y)^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/b3fp1lu5ffaqm3bxq8r55qkycn7ltkemwb.png)
Factor out 2(c+y)^2 from the expression:
![2(c+y)^3-14(c+y)^2-6(c+y)^4=2(c+y)^2\lbrack(c+y)-7-3(c+y)^2\rbrack](https://img.qammunity.org/2023/formulas/mathematics/high-school/mxf6yt2a359vhiip7670p6qnmjyvi52czu.png)
Therefore, the answer is option A and the expression inside the box should be:
![2(c+y)^2((c+y)-7-3(c+y)^2)](https://img.qammunity.org/2023/formulas/mathematics/high-school/9dipbj5y4tx2kjb54h0te1tsuv0uupveiz.png)