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If x2 - 3x - 1 = 0, then the value of (x2 + 8x - 1)(x3 + x-1)-1 is:
Answer & Solution
Correct Answer:
Option
C
$$\eqalign{
& {x^2} - 3x - 1 = 0 \cr
& x\left( {x - 3 - \frac{1}{x}} \right) = 0 \cr
& x - \frac{1}{x} = 3 \cr
& {x^2} + \frac{1}{{{x^2}}} = 11 \cr
& \frac{{\left( {{x^2} + 8x - 1} \right)}}{{{x^3} + \frac{1}{x}}} \cr
& = \frac{{x\left( {\frac{{x - 1}}{{x + 8}}} \right)}}{{x\left( {\frac{{{x^2} + 1}}{{{x^2}}}} \right)}} \cr
& = \frac{{3 + 8}}{{11}} \cr
& = 1 \cr} $$
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