Question

answer the questions given in the picture​

Answer 1

(1)=ans 140

explaination

x-1/x=5

taking cube both sides

(x-1/x)^3=125

x^3-1/x^3-3×x×1/x(x-1/x)=125

x^3-1/x^3-3×5=125

x^3-1/x^3=125+15

x^3-1/x^3=140