A3 + b3 + 3AB(a + B) = (a + b)3X3 + 1/X3 + 3(x + 1/x) = 54√2x3 + 1/x3 + 9√2 = 54√2x3 + 1/x3 = 45√2∴ (x2 + 1/x2) (x3 + 1/x3) = 16 × 45√2x5 + x + 1/x + 1/x5 = 720√2x5 + 1/x5 + 3√2 = 720√2x5 + 1/x5 = 717√2