If x^4+1/x^4=119, then the value of x^3-1/x^3 is
a)+ or - 36 b) + or - 33 c)36 d) -36

• x^4 + 1/x^4 = 119
  or, (x^2+1/x^2)^2 - 2 = 119
  or, (x^2+1/x^2)^2 = 121
  or, x^2+1/x^2 = 11 [considering +ve value]
  or, (x - 1/x)^2 +2 = 11
  or, (x - 1/x)^2 = 9
  or, x - 1/x = +-3
  
  Now, x^3 - 1/x^3
  =(x - 1/x)^3 + 3*x*1/x*(x - 1/x)
  =(3)^3 + 3 * 3 or, =(-3)^3 + 3*(-3)
  =27 + 9 =-27 - 9
  =36 = -36
  
  so Ans: a) + or - 36
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