A) \[\pm 3,\ \pm 1\]
B) \[\pm 3,\ \pm i\]
C) \[\pm 2,\ \pm i\]
D) None of these
Correct Answer: B
Solution :
Equation \[{{x}^{4}}-8{{x}^{2}}-9=0\] Þ \[{{x}^{4}}-9{{x}^{2}}+{{x}^{2}}-9=0\]Þ \[{{x}^{2}}({{x}^{2}}-9)+1({{x}^{2}}-9)=0\] Þ \[({{x}^{2}}+1)({{x}^{2}}-9)=0\Rightarrow x=\pm i,\,\,\pm 3\].You need to login to perform this action.
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