$\begin{aligned}
& \text { As } A \operatorname{adj} A=|A| l, \operatorname{det}(\lambda A)=\lambda^n \operatorname{det} A \
& \operatorname{det}(3 \operatorname{adj}(-6 \operatorname{adj}(3 A)))=3^3 \operatorname{det}(\operatorname{adj}(-6 \operatorname{adj}(3 A))) \
& =3^3(-6 \operatorname{adj}(3 A))^2 \
& =3^3(-6)^6|3 A|^4 \
& =3^9 2^6 \cdot 3^{12} \cdot(-2)^4 \
& =3^{21} \cdot 2^{10}
\end{aligned}Nowcomparingwithgivencondition\begin{aligned}
& 2^{m+n} 3^{m n}=2^{10} \cdot 3^{21} \
& m+n=10, m n=21 \
& \Rightarrow \quad m=7, n=3(m>n) \
& \therefore \quad 4 m+2 n=28+6=34
\end{aligned}$
Let A be a square matrix of order 3 such that det(A)=-2 and det(3 adj(-6 adj(3 A)))=2^ m+ n · 3^ mn, mgt n. Then 4 ~m+2 n is equal to
JEE Main 2025 — Mathematics Algebra
Let A be a square matrix of order 3 such that det(A)=−2 and det(3adj(−6adj(3A)))=2m+n⋅3mn,m>n. Then 4 m+2n is equal to _______
Held on 22 Jan 2025 · Verified 6 Jul 2026.
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