GIVEN:x4 + x-4 = 194Identity used:(a + b)2 = a2 + b2 + 2abCalculation:x4 + x-4 = 194Adding 2 on both sidesx4 + x-4 + 2 = 194 + 2⇒ (x2 + 1/x2)2 = 196 = 142⇒ x2 + 1/x2 = 14Again ADDING 2 on both sidesx2 + 1/x2 + 2 = 14 + 2⇒ (x + 1/x)2 = 16 = 42 ∴ x + 1/x is 4