The expression (x – y)(x² + xy + y²) + (x + y)(x² – xy + y²) – (x + y)(x² – y²) is equal to

Using identities: (x-y)(x²+xy+y²) = x³-y³ and (x+y)(x²-xy+y²) = x³+y³. So the first two terms sum to 2x³. The third term: (x+y)(x²-y²) = (x+y)²(x-y) = (x+y)(x+y)(x-y). Expanding: (x+y)(x²-y²) = x³ - xy² + x²y - y³ = x³ + x²y - xy² - y³. So expression = 2x³ - (x³ + x²y - xy² - y³) = x³ + y³ - x²y + xy² = x³ + y³ + xy(y - x). Reviewing options, this matches option (3). However, the form x³ + y³ + xy(x-y) = x³ + y³ + x²y - xy². Checking carefully: 2x³ - x³ - x²y + xy² + y³ = x³ + y³ - x²y + xy² = x³ + y³ + xy(y-x). This matches option (3).