2x - 1/x = 8
64 = 8² = (2x - 1/x)² = 4x² - 2 * 2x * 1/x + 1/x² = 4x² + 1/x² - 4
4x² + 1/x² = 64 + 4 = 68
2x - 1/x = 8
64 = 8² = (2x - 1/x)² = 4x² - 2 * 2x * 1/x + 1/x² = 4x² + 1/x² - 4
4x² + 1/x² = 64 + 4 = 68