​ If |(4,3),(3,1)| = -5 then the value of |(20,15),(15,5)| is: (a) -5 (b) -125 (c) -25 (4) 0 ​

Question

If \( \begin{vmatrix} 4&3\\3&1 \end{vmatrix}\) = -5 then the value of \( \begin{vmatrix} 20&15\\15&5 \end{vmatrix}\) is: 

(a) -5 

(b) -125 

(c) -25 

(4) 0

Answer 1

(b) -125

\( \begin{vmatrix} 20&15\\15&5 \end{vmatrix}\)

= 5 x 5 \( \begin{vmatrix} 4&3\\3&1 \end{vmatrix}\)

= 5 x 5 x (-5) 

= -125