If x + 1/x = 6, then x 4 + 1/x 4 is?

x + 1/x = 6
On squaring both sides, we get
(x + 1/x)² = (6)²
⇒ x² + 1/x² + 2 = 36
⇒ x² + 1/x² = 34
On squaring both sides, we get
(x² + 1/x²)² = (34)²
⇒ x⁴ + 1/x⁴ + 2 = 1156
⇒ x⁴ + 1/x⁴ = 1154