Step-by-step explanation:
x³ - y³ = (x - y)³ + 3x²y - 3xy²
28 = (2)³ + 3xy(x - y)
28 = 8 + 3xy(2)
28 - 8 = 6xy
20 = 6xy → xy = 20/6 = 10/3
(x - y)² = 2²
x² - 2xy + y² = 4
x² - 2(10/3) + y² = 4
x² + y² = 4 + 20/3 = 32/3
x² + xy + y² = 32/3 + 10/3 = 42/3 = 14
