A) 3, 7
B) 4, 7
C) 3, 9
D) 3, 4
Correct Answer: A
Solution :
Given,\[\left| \begin{matrix} 3 & 5 & x \\ 7 & x & 7 \\ x & 5 & 3 \\ \end{matrix} \right|=0\] \[\Rightarrow \] \[3(3x-35)-5(21-7x)+x(35-{{x}^{2}})=0\] \[\Rightarrow \] \[9x-105-105+35x+35x-{{x}^{3}}=0\] \[\Rightarrow \] \[{{x}^{3}}-79x+210=0\] \[\Rightarrow \] \[(x+10)(x-3)(x-7)=0\] \[\Rightarrow \] \[x=10,\,\,3,\,\,7\]You need to login to perform this action.
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