Sum and Difference of cubes

What goes in the second parenthesis?

$$\left(4x-2\right)\left(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \right)$$  

Which cubes are being subtracted?

$$??\ =\left(4x-2\right)\left(16x^2+8x+4\right)$$  

Select the difference of cubes factorization that is correct

In what term of the second parenthesis, there's an error in the sum of cubes factorization.

$$\left(3x+4y\right)\left(6x^2+12xy+16y\right)$$  

Select all that are incorrect

In what term of the second parenthesis, there's an error in the sum of cubes factorization.

$$\left(4x+2y\right)\left(16x^2-8y+4y^2\right)$$  

Select all that are incorrect

In what term of the second parenthesis, there's an error in the sum of cubes factorization.

$$\left(xy^2+z\right)\left(xy^2+2xyz-y^2\right)$$  

Select all that are incorrect

Which cubes are being subtracted or added?

$$??\ =\left(4x-2y\right)\left(16x^2+8xy+4y^2\right)$$  

Which cubes are being subtracted or added?

$$??\ =\left(xy^2+z\right)\left(x^2y^4+xy^2z+z^2\right)$$