Question

Please tell fast this 3 Ques

Answer 1

I don't know but put 5 on x

Answer 2

x-1/x=5
cubing in b.h.s
(x-1/x)^3=5^3
x^3-1/x^3-3x1/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

I hope it helps you