Answer-If x – 1/x = 9, then x3 – 1/x3 is:

Since, x ndash 1x 15 Cubing both sides we get x3 ndash 1x3 ndash 3 times x times 1x times x ndash 1x 729 Or x3 ndash 1 x3 1331 3 times 9 729 27 756 Alternate method If it is given, x ndash 1x n and we have to find x3 ndash 1x3, can directly use n3 3n. x ndash 1x 9 By using n3 3n, where n 9 gt 93 3 times 9 gt 729 27 756