xy=-6, x+y=7, Найти x³+y³

x³ + y³ = (x + y)(x² -xy + y²)

x² + y² = (x + y)² - 2xy = 7² - 2 * (- 6) = 49 + 12 = 61

x³ + y³ = 7 * [61 - (- 6)] = 7 * (61 + 6) = 7 * 67 = 469