x⁴ + x² + 1 = 5x² হলে x + 1/x এর মান কত?

দেয়া আছে,
x⁴ + x² + 1 = 5x²
x⁴ + 1 = 5x² - x²
x⁴ + 1 = 4x²
(x⁴ + 1)/x² = 4x²/x²
x⁴/x² + 1/x² = 4
x² + 1/x² = 4
(x + 1/x)² - 2x.1/x = 4
(x + 1/x)² - 2 = 4
(x + 1/x)² = 6
x + 1/x = √6