If = | a h g h b f g f c | , then the cofactor A 21 is:

Question

If $Δ =$ $| \begin{matrix} a & h & g \\ h & b & f \\ g & f & c \end{matrix} |$ $,$ then the cofactor $A_{21}$ is:

Smart Achievers · Accepted Answer

(2)

Ans. $| \begin{matrix} a & h & g \\ h & b & f \\ g & f & c \end{matrix} |$

Explanation:

$A_{21} = {(- 1)}^{2 + 1} M_{21}$

$= - M_{21} = -$ $| \begin{matrix} h & g \\ f & c \end{matrix} |$

$= - (h c - f g)$

$= f g - h c$

Want Us to Email you About Special Offers & Updates?