$A=1,B=2,$ and so on$.$ Thus, for example, "ABORT MISSION" becomes

$\left[\begin{array}{ccccccccccccc}1& 2& 15& 18& 20& 0& 13& 9& 19& 19& 9& 15& 14\end{array}\right].$

of numbers in the form of a matrix with two rows $($using zero in the last place if we have an odd number of characters$)$ and then multiply on the left be

Encrypted Matrix $=\left[\begin{array}{ccc}4& 1& 2\end{array}\right]$

$3\left[\begin{array}{ccccccccccccc}1& 15& 20& 13& 19& 9& 14& 18& 0& 9& 19& 15& 0\end{array}\right]$

$2$

$=\left[\begin{array}{ccccccccccccc}6& 78& 80& 61& 95& 51& 56& 81& 60& 57& 95& 57& 42\end{array}\right]$

$7$

which we can also write as

$\left[\begin{array}{cccccccccccccc}6& 7& 78& 81& 80& 60& 61& 57& 95& 95& 51& 57& 56& 42\end{array}\right].$

To decipher the encoded message, multiply the encrypted matrix by $A^{-1}.$ The following question uses the above matrix A for encoding and decoding.

Decode the following message, which was encrypted using the matrix $A.($Include any appropriate spaces in your answer.$)$

$\left[\begin{array}{cccccccccccccc}27& 39& 90& 90& 23& 21& 80& 60& 18& 31& 99& 103& 38& 51\end{array}\right]$