if x + (1/x) = 3
then x^5 + (1/x^5)== ?
123,126,113,129

• 123
  
  x + (1/x) = 3
  x^2 + (1/x^2) = 9-2=7
  x ^4+ (1/x^4) =7^2-2=47
  x^3 + (1/x^3) = 3^3 -3*x*(1/x)(x+1/x)= 18
  [x + (1/x)]*[x ^4+ (1/x^4)] = 3*47=141
  x^5 + (1/x^5)= 141-18=123
• 11 years agoHelpfull: Yes(6) No(1)
• got it ! thanks karan !
• 11 years agoHelpfull: Yes(0) No(2)
• ans : 123
  
  explanation:
  from the given equation we can get,
  x^2+1/x^2=7
  and
  x^3+1/x^3=18
  
  x^5+1/x^5=(x^2+1/x^2)(x^3+1/x^3)-(x+1/x)=7*18-3=126-3=123
  
  
• 11 years agoHelpfull: Yes(0) No(0)