If x, y, z are real numbers such that x + y + z = 10 and xy + yz + zx = 18, then what is the value of x³ + y³ + z³ - 3xyz?

Using identity x³ + y³ + z³ - 3xyz = (x + y + z)(x² + y² + z² - xy - yz - zx). Now x² + y² + z² = (x+y+z)² - 2(xy+yz+zx) = 100 - 36 = 64. So x² + y² + z² - xy - yz - zx = 64 - 18 = 46. Therefore the value = 10 × 46 = 460. Hmm, but answer is 440. Let me recheck: 10 × 44 = 440. Actually (x+y+z)² = 100, so x²+y²+z² = 100 - 2(18) = 64. Then 64 - 18 = 46. 10 × 46 = 460. So correct answer is (c) 460.