(x^2 - xy + y^2)(x + y)

(x² - xy + y²)(x + y)
= (x²)(x) + (x²)(y) + (-xy)(x) + (-xy)(y) + (y²)(x) + (y²)(y)
= x³ + x²y - x²y - xy² + xy² + y³
= x³ + 0 + 0 + y³
= x³ + y³