MHT CET · Maths · Determinants
If \(A=\left[\begin{array}{ccc}5 & 6 & 3 \\ -4 & 3 & 2 \\ -4 & -7 & 3\end{array}\right]\), then cofactors of all elements of second row are respectively.
- A \(-39,3,11\)
- B \(-39,27,11\)
- C \(39,-3-11\)
- D \(-39,-27,11\)
Answer & Solution
Correct Answer
(B) \(-39,27,11\)
Step-by-step Solution
Detailed explanation
\(
A=\left[\begin{array}{ccc}
5 & 6 & 3 \\
-4 & 3 & 2 \\
-4 & -7 & 3
\end{array}\right]
\)
Cofactors of elements in second row are
Cofactor of -4
Cofactor of 3
\(
\begin{aligned}
& =(-1)^{2+1}\left|\begin{array}{cc}
6 & 3 \\
-7 & 3
\end{array}\right|=-(18+21)=-39 \\
& =(-1)^{2+2}\left|\begin{array}{cc}
5 & 3 \\
-4 & 3
\end{array}\right|=15+12=27 \\
& =(-1)^{2+3}\left|\begin{array}{cc}
5 & 6 \\
-4 & -7
\end{array}\right|=-(-35+24)=11
\end{aligned}
\)
A=\left[\begin{array}{ccc}
5 & 6 & 3 \\
-4 & 3 & 2 \\
-4 & -7 & 3
\end{array}\right]
\)
Cofactors of elements in second row are
Cofactor of -4
Cofactor of 3
\(
\begin{aligned}
& =(-1)^{2+1}\left|\begin{array}{cc}
6 & 3 \\
-7 & 3
\end{array}\right|=-(18+21)=-39 \\
& =(-1)^{2+2}\left|\begin{array}{cc}
5 & 3 \\
-4 & 3
\end{array}\right|=15+12=27 \\
& =(-1)^{2+3}\left|\begin{array}{cc}
5 & 6 \\
-4 & -7
\end{array}\right|=-(-35+24)=11
\end{aligned}
\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Maths
- The number of solutions of \(16^{\sin ^2 x}+16^{\cos ^2 x}=10\) in \(0 \leqslant x \leqslant 2 \pi\) areMHT CET 2025 Medium
- The growth of population is proportional to the number present. If the population of a colony doubles is 50 years, then the population will become triple in _____ yearsMHT CET 2020 Medium
- \(\int \frac{e^{x}}{\sqrt{x}}(1+2 x) d x=\)MHT CET 2020 Easy
- If \(\sin \left(\theta^{\circ}-\alpha\right), \sin \theta\) and \(\sin (\theta+\alpha)\) are in H.P., then the value of \(\cos ^2 \theta\) isMHT CET 2024 Medium
- \(\lim _{x \rightarrow 2}\left[\frac{1}{x-2}-\frac{2}{x^3-3 x^2+2 x}\right]\) is equal toMHT CET 2023 Easy
- If the probability distribution function of a random variable \(\mathrm{X}\) is given as

Then \(F(0)\) is equal toMHT CET 2021 Easy
More PYQs from MHT CET
- The coordination number of the sphere in cubic close packed (ccp) structure isMHT CET 2020 Easy
- The ratio of radii of gyration of a ring to a disc (both circular) of same radii and mass, about a tangential axis perpendicular to the plane isMHT CET 2020 Easy
- The number of common tangents to the circles \(x^2+y^2-x=0\) and \(x^2+y^2+x=0\) is /areMHT CET 2024 Easy
- Glycerine of density \(1.25 \times 10^3 \mathrm{~kg} / \mathrm{m}^{3^4}\) is flowing in conical shaped horizontal pipe. Crosssectional area of the pipe at its both ends is \(10 \mathrm{~cm}^2\) and \(5 \mathrm{~cm}^2\) respectively. Pressure difference at both the ends is \(3 \mathrm{~N} / \mathrm{m}^2\). Rate of flow of liquid in the pipe isMHT CET 2024 Hard
- What is the conductivity of 0.05 M NaOH solution having resistance 31.5 ohm and cell constant \(0.315 \mathrm{~cm}^{-1}\) ?MHT CET 2024 Easy
- The molecule in which central atom does NOT undergo \(\mathrm{sp}^3\) hybridisation isMHT CET 2022 Easy