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If x+1/(x)=8, then the value of (x-1/(x)...

If `x+1/(x)=8`, then the value of `(x-1/(x))^(2)` is

A

64

B

60

C

16

D

62

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem where \( x + \frac{1}{x} = 8 \) and we need to find the value of \( \left( x - \frac{1}{x} \right)^2 \), we can follow these steps: ### Step 1: Start with the given equation We have: \[ x + \frac{1}{x} = 8 \] ### Step 2: Square both sides To find \( \left( x - \frac{1}{x} \right)^2 \), we first square the left-hand side: \[ \left( x + \frac{1}{x} \right)^2 = 8^2 \] This gives us: \[ x^2 + 2 \cdot x \cdot \frac{1}{x} + \frac{1}{x^2} = 64 \] Since \( x \cdot \frac{1}{x} = 1 \), we can simplify this to: \[ x^2 + 2 + \frac{1}{x^2} = 64 \] ### Step 3: Rearrange the equation Now, we can rearrange the equation to isolate \( x^2 + \frac{1}{x^2} \): \[ x^2 + \frac{1}{x^2} = 64 - 2 \] This simplifies to: \[ x^2 + \frac{1}{x^2} = 62 \] ### Step 4: Use the identity for \( \left( x - \frac{1}{x} \right)^2 \) We know that: \[ \left( x - \frac{1}{x} \right)^2 = \left( x + \frac{1}{x} \right)^2 - 4 \cdot x \cdot \frac{1}{x} \] Substituting the values we have: \[ \left( x - \frac{1}{x} \right)^2 = (x^2 + \frac{1}{x^2}) - 2 \] Now substituting \( x^2 + \frac{1}{x^2} = 62 \): \[ \left( x - \frac{1}{x} \right)^2 = 62 - 2 \] This gives us: \[ \left( x - \frac{1}{x} \right)^2 = 60 \] ### Final Answer Thus, the value of \( \left( x - \frac{1}{x} \right)^2 \) is: \[ \boxed{60} \]
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