Answers

The Brainliest Answer!
2015-01-09T14:01:06+05:30
 x^{2} + \frac{1}{ x^{2} } =98 \\  \\  x^{2} + \frac{1}{ x^{2} } +2x( \frac{1}{x}) =98+2 \\  \\  (x+1/x)^{2} =100= 10^{2}  \\  \\ x+1/x = 10 

x+1/x = 10 ----------(1)
And,
 (x+1/x)³ = 10³
  x³ + (1/x)³ + 3x.1/x(x+1/x) = 1000
  x³+ 1/x³ + 3(10)  = 1000    ..               (from eqn 1)
  x³ + 1/x³ =1000-30
  x³+ 1/x³ = 970
2 4 2
2015-01-09T14:22:48+05:30
X² + 1/x² = 98
add 2 on both the sides and by doing that you will get
x² + 1/x² +2 = 100
or you can write it as
(x + 1/x )² =10²
⇒(x + 1/x ) = 10
cube on both sides
x³ +1/x³ =3x.1/x(x+1/x) = 1000
⇒we already know (x + 1/x ) = 10
so
x³ +1/x = 1000 - 30 = 970
so the answer in 970...



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