A) \[3,\,\,-1\]
B) \[-3,\,\,1\]
C) 3, 1
D) \[-3,\,\,-1\]
Correct Answer: A
Solution :
\[\left| \,\begin{matrix} x & 2 & -1 \\ 2 & 5 & x \\ -1 & 2 & x \\ \end{matrix}\, \right|=0\]Þ\[x(5x-2x)-2(2x+x)-1(4+5)=0\] Þ \[3{{x}^{2}}-6x-9=0,{{x}^{2}}-2x-3=0\],\[(x+1)(x-3)=0\] \[\Rightarrow x=-1,\,3\].You need to login to perform this action.
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