NDA 2015
- Exam
- NDA
- Year
- 2015
- Subject
- Mathematics
- Chapter
- Matrices
NDA 2015 · Mathematics · Matrices
If X=[ array ll 3 & -4 1 & -1 array ], B=[ array cc 5 & 2 -2 & 1...
If \quad X=\left[\right], B=\left[\right] and A=\left[\right] satisfy the equation , then the matrix is equal to
Options
- A\left[\right]
- B\left[\right]
- C\left[\right]
- D\left[\right]
Correct answer
A. \left[\right]
Step-by-step solution
\mathrm{X}=\left[\right], \mathrm{B}=\left[\right] and \mathrm{A}=\left[\right]
Now, \mathrm{AX}=\mathrm{B}\therefore \quad\left[\right]\left[\right]=\left[\right]\Rightarrow\left[\right]=\left[\right]\begin{array}{ll} & -p=7 \\
\therefore \quad & p=-7 \\
\Rightarrow \quad q=5-3(-7) \\
& q=26
\end{array}\begin{aligned}& \therefore \quad \mathrm{r}=1 \\ \text{ and } \Rightarrow \quad \mathrm{ s}=-2-3=-5 \\ \text{ and } \therefore \quad \mathrm{ s}=-5
\end{aligned}$
Hence, $A=\left[\begin{array}{ll}\mathrm{p}& \mathrm{q}\\ \mathrm{r}& \mathrm{s}\end{array}\right]=\left[\begin{array}{cc}-7 & 26 \\ 1 & -5\end{array}$\right]\therefore \quad Option (A) is correct.