MCQ
Let $A$ and $B$ be two $3 \times 3$ non-zero real matrices such that $AB$ is a zero matrix. Then.
  • A
    The system of linear equations $AX =0$ has a unique solution
  • The system of linear equations $AX =0$ has infinitely many solutions
  • C
    $B$ is an invertible matrix
  • D
    $\operatorname{adj}$ $(A)$ is an invertible matrix

Answer

Correct option: B.
The system of linear equations $AX =0$ has infinitely many solutions
b
$AB =0 \Rightarrow| AB |=0$

If $| A | \neq 0, B =0$ (not possible)

If $| B | \neq 0, A =0$ (not possible)

Hence $| A |=| B |=0$

$AX =0$ has infinitely many solutions

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

If the vectors $2i + j - k,\, - i + 2j + \lambda k$ and $ - 5i + 2j - k$ are coplanar, then the value of $\lambda $ is equal
If $f(n) = \tan ^{{  - 1 }} \left( {\frac{e-1}{e^{-n}+e^{n+1}}} \right)$$\forall n\, \in \,N$ , then $\sum\limits_{n = 1}^\infty  {f\left( n \right)} $ is equal to
Let $f : R \rightarrow R$ be a function defined by $f ( x )=$ $\log _{\sqrt{m}}\{\sqrt{2}(\sin x-\cos x)+m-2\}$, for some $m$, such that the range of $f$ is $[0,2]$. Then the value of $m$ is $............$
Let $S = \{\lambda ,\mu \} \in R \times R:f\left( t \right) = \left( {\left| \lambda  \right|{e^{\left| t \right|}} - \mu } \right)$. $\sin \left( {2\left| t \right|} \right),t \in R$ , is a differentiable function$\}$ . Then $S$ is a subest of?
$\left| {\,\begin{array}{*{20}{c}}{a - 1}&a&{bc}\\{b - 1}&b&{ca}\\{c - 1}&c&{ab}\end{array}\,} \right| = $
If the vectors  $a $ and $b$  are mutually perpendicular, then $a \times \{ a \times \{ a \times (a \times b)\} \} $ is equal to
Let $\mathrm{P}(\alpha, \beta, \gamma)$ be the image of the point $\mathrm{Q}(3,-3,1)$ in the line $\frac{x-0}{1}=\frac{y-3}{1}=\frac{z-1}{-1}$ and $R$ be the point $(2,5,-1)$. If the area of the triangle $\mathrm{PQR}$ is $\lambda$ and $\lambda^2=14 \mathrm{~K}$, then $\mathrm{K}$ is equal to:
The direction ratios of the normal to the plane 7x + 4y - 2z + 5 = 0 are:
  1. 7, 4, -2
  2. 7, 4, 5
  3. 7, 4, 2
  4. 4, -2, 5
Let $\text{f}:[2,\infty)\rightarrow\ \text{X}$ be defined by f(x) = 4x - x2. Then, f is invertible if X =
  1. $[2,\infty)$
  2. $(-\infty,2]$
  3. $(-\infty,4]$
  4. $[4,\infty)$
The domain of the function $f(x)=\sin ^{-1}\left[2 x^{2}-3\right]+\log _{2}\left(\log _{\frac{1}{2}}\left(x^{2}-5 x+5\right)\right)$ where $[ t ]$ is the greatest integer function, is.