Question

please solve this problem ​

Answer 1

None is the correct answer

Answer 2

Question

$\sf \left[ \begin{array}{c c c} 2& -1&4 \\ 0& - 2&5\\ - 3&1&3\end{array}\right]$

To Find

co-factor of -1

$\sf\huge\bold{\underline{\underline{{Solution}}}}$

B. -15

We have to find minor then we can find Co-factor

Minor is denoted by 'M'

and Co-factor is denoted by 'A'

$\sf \left[ \begin{array}{c c c} 2& -1&4 \\ 0& - 2&5\\ - 3&1&3\end{array}\right]$

=>-1 is the second element of first row

so, we have to find Minor of first row of second element.

$\sf M_{12} = \sf \left[ \begin{array}{c c c} 0& 5\\ 0&- 3\end{array}\right]$

$\sf \longmapsto0 - ( - 15) = 15$

$\sf \longmapsto \: M_{12} = 15$

Now ,finding Co-factor

$\sf \longmapsto \: A_{12} = {( - 1)}^{1 + 2} (15) = - 15$

$\sf\therefore{\bold{A_{12}=-15}}$

Co-factor of -1 is -15.