if a power 4 +(1/a)power 4=119 then a power 3-(1/a)power 3=
a)32 b)39 c)data not sufficient

• Since a power 4 +1/a poeer 4 = 119
  
  step 1. Re write the question as-
  => (a square) power 2 + 1/(a square 2) power 2 = 119
  
  step 2 - add 2 and substract 2 on left side
  => (a square) power 2 + 1/(a square 2) power 2 + 2 -2= 119
  
  step 3- apply (A+B)s quare = A square + B square + 2 *A *B
  => (a square) power 2 + 1/(a square 2) power 2 + 2((a square) power 2) * (1/(a square 2) power 2) - 2((a square) power 2) * (1/(a square 2) power 2)= 119
  => ((a square ) + 1/ (a square) ) )square = 119 + 2 = 121
  => (a square ) + 1/ (a square) ) = square root of (121)
  =>(a square ) + 1/ (a square) ) = 11 .....................................En(1)
  
  step 4- substract 2 and add 2 on left side
  =>(a square ) + 1/ (a square) ) - 2 + 2 = 11
  => (a square ) + 1/ (a square) ) - 2 * (a square ) + 1/ (a square) + 2 (a square ) + 1/ (a square) = 11
  => (a - 1/a) square = 11-2 = 9
  => a - 1/a = square root of 9
  => a - 1/a = 3.....................................En(2)
  
  NOW problem is-
  =a power 3 - 1/a power 3
  = (a - 1/a) * (a sqaure + (a square) * (1/a square) + 1/a square)
  = 3 * (a sqaure + 1/a square + 1) [ FROM EQN(2) ]
  = 3 * ( 11 + 1) [ FROM EQN(1) ]
  = 3 * 12
  =36 ANS
  
  
  
  
• 8 years agoHelpfull: Yes(10) No(0)
• sorry correct formula is
  x^3-1/x^3=(x-1/x)(x^2+x.1/x+1/x^2)
  3.(11+1)
  36 is correct ans
• 8 years agoHelpfull: Yes(6) No(0)
• Ans =36
  and options is 32
  36
  39
  can not determine
  
  
  
• 8 years agoHelpfull: Yes(1) No(0)
• a power4 +(1/a)power4=119
  ((a power4)square+1) / a power 4=119
  now apply the formula of (a square+b square)=(a+b)sauare-2ab;
  
  (a power4 + 1) square -2*a power4=119* a power4
  (apower4+1)square =121 *apower4
  (apower4+1)= square root(121*apower4)
  or (apower4+1) =11*a square;
  apower4-11a square +1=0 now we have a equation solve this and get a value of 'a'
  
  
  final answer should be approx 81
• 8 years agoHelpfull: Yes(0) No(0)
• x^4+1/x^4=119
  let x2=y
  y^2+1/y^2=119
  (y+1/y)^2-2.y.1/y=119
  (y+1/y)^2=121
  y+1/y=11 eq 1
  x^2+1/x^2=11
  (x-1/x)^2+2.x.1/x=11
  (x-1/x)^2=9
  x-1/x=3 eq 2
  x^3-1/x^3=(x-1/x)(x^2-x.1/x+1/x^2)
  3.(11-1)
  30 is ans
  
• 8 years agoHelpfull: Yes(0) No(4)
• use a3-b3= (a-b) (a2+ab+b2)
  a4-b4=(a2+b2)2
• 8 years agoHelpfull: Yes(0) No(0)
• a^4+1/a^4=119,(a2)^2++1/(a2)^2+2*a2*1/a^2-2*a^2*1/a2
  (a2+1/a2)^2-2=119 a2+1/a2=11
  a3-1/a3=(a-1/a)(a2+1/a2+2)
  a-1/a=3
  13*3=39
• 8 years agoHelpfull: Yes(0) No(1)