Find the 2 3th entry of the inverse of the matrix 1 2 3 1 3

Find the (2, 3)-th entry of the inverse of the matrix [1 2 3 1 3 2 2 1 4] 3/5 2/5 -3/5 1/5 -1/5

Solution

A=(4  1   5)230112701

\\displaystyle={\\left(-{8}+{\\left(-{3}\ ight)}+{0}\\ \\ \\ {4}+{1}+{10}\\ \\ \\ {28}+{0}+{\\left(-{5}\ ight)}\ ight)}=(8+(3)+0   4+1+10   28+0+(5))

\\displaystyle={\\left(-{11}\\ \\ {15}\\ \\ {23}\ ight)}=(11  15  23)

AB is not possible. (3 × 3) × (1 × 3).