Final answer:
To develop a polynomial identity, square one factor from column A and add it to one factor from column B.
Step-by-step explanation:
To develop a polynomial identity, we need to square one factor from column A and add it to one factor from column B.
Let's take the first option: (x + y) (x² + 2xy + y²)
Squaring the first factor, we get (x + y)² = x² + 2xy + y²
Adding it to the second factor, we have x² + 2xy + y² + (x2 + 2xy + y2)
Combining like terms, we get 2x² + 4xy + 2y²
Therefore, the polynomial identity is 2x² + 4xy + 2y².