The multiplicative inverse of matrix [ * 20 c 2&1 7&4 ]is - Vidyadip

MCQ

The multiplicative inverse of matrix $\left[ {\begin{array}{*{20}{c}}2&1\\7&4\end{array}} \right]$is

A
$\left[ {\begin{array}{*{20}{c}}4&{ - 1}\\{ - 7}&{ - 2}\end{array}} \right]$
B
$\left[ {\begin{array}{*{20}{c}}{ - 4}&{ - 1}\\7&{ - 2}\end{array}} \right]$
C
$\left[ {\begin{array}{*{20}{c}}4&{ - 7}\\7&2\end{array}} \right]$
✓
$\left[ {\begin{array}{*{20}{c}}4&{ - 1}\\{ - 7}&2\end{array}} \right]$

✓

Answer

Correct option: D.

$\left[ {\begin{array}{*{20}{c}}4&{ - 1}\\{ - 7}&2\end{array}} \right]$

d
(d) From option check $A{A^{ - 1}} = I$.

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