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Question: Answered & Verified by Expert
If $\left|\begin{array}{ccc}a^{2} & b c & c^{2}+a c \\ a^{2}+a b & b^{2} & c a \\ a b & b^{2}+b c & c^{2}\end{array}\right|=k a^{2} b^{2} c^{2}$, then $k=$
MathematicsDeterminantsWBJEEWBJEE 2020
Options:
  • A 2
  • B $-2$
  • C $-4$
  • D 4
Solution:
1909 Upvotes Verified Answer
The correct answer is: 4
Hint:
$\left|\begin{array}{ccc}a^{2} & b c & c^{2}+a c \\ a^{2}+a b & b^{2} & c a \\ a b & b^{2}+b c & c^{2}\end{array}\right|=(a b c)\left|\begin{array}{ccc}a & c & a+c \\ a+b & b & a \\ b & b+c & c\end{array}\right|$
opening through $\mathrm{R}-1=4 \mathrm{a}^{2} \mathrm{~b}^{2} \mathrm{C}^{2}$

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