Math, asked by kartikay2114, 1 year ago

x=5√2-7 find the value of x^3-1/x^3

Answers

Answered by praneethks
1
x^3-1/x^3 okaynow x^3-1/x^3=(x-1/x)(x^2+1/x^2 +1)=(5√2-7-(5√2+7))(196+3)=-2786
Answered by sandy1816
0

x = 5 \sqrt{2}  - 7 \\  \\  \frac{1}{x}  =  \frac{1}{5 \sqrt{2} - 7 }  \\   \frac{1}{x}  =  \frac{5 \sqrt{2}  + 7}{50 - 49}  \\  \frac{1}{x}  = 5 \sqrt{2}  + 7 \\  \\ x -  \frac{1}{x}  = 5 \sqrt{2}  - 7 - 5 \sqrt{2}  - 7 \\  =  - 14 \\  \\  {x}^{3}  -  \frac{1}{ {x}^{3} }  = ( {x -  \frac{1}{x} })^{3}  + 3(x -  \frac{1}{x} ) \\  = ( { - 14})^{3}  + 3( - 14) \\  =  - 2744 - 52 \\  =  - 2796

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