Question

if x+1/x=7 then what is the value of x^3+1/x^3

Answer 1

(x+1/x)^3 = x^3+ (1/x)^3 +3(.x.)(1/x)(x+1/x)

(7)^3= x^3+1/x^3 +3(x+1/x)
343= x^3+1/x^3+ 3x7
343-21= x3+ 1/x3
x^3+1/x^3= 322