if 1 x8 65 and x4 64 the value of, Surds and Indices, General Mathematics

Question:If` 1 - x^8 = 65` and` 1 - x^4 = 64,` the value of x is :

A `+ 1/sqrt(2)`
  - 
B `+ sqrt(2)`
  - 
C `+ 1/(2sqrt(2)`
  - 
D `+ 2sqrt(2)`
  -

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+ AnswerC

+ ExplanationOn diving, we get` (1 - x^8)/(1 - x^4) `

    `= 65/64`

`or ((1 - x^4) (1 + x^4))/((1 - x^4))`

`= 65/64 or 1 + x^4`

`= 65/64`

`:. x^4 = (65/64 - 1)`

`= 1/64 or x = (1/2^6)^(1/4)`

`= + 1/(2^(3/2))`
      -

`= + 1/(2sqrt(2))`
      -

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Question:If` 1 - x^8 = 65` and` 1 - x^4 = 64,` the value of x is :

A `+ 1/sqrt(2)` -

B `+ sqrt(2)` -

C `+ 1/(2sqrt(2)` -

D `+ 2sqrt(2)` -

C