Given: A=132−14−12−53
The minor of an element aij is the determinant of the matrix obtained by deleting row i and column j.
For b11, delete row 1 and column 1:
[4−1−53]
b11=(4)(3)−(−5)(−1)
b11=12−5
b11=7
For b12, delete row 1 and column 2:
[32−53]
b12=(3)(3)−(−5)(2)
b12=9+10
b12=19
For b13, delete row 1 and column 3:
[324−1]
b13=(3)(−1)−(4)(2)
b13=−3−8
b13=−11
For b21, delete row 2 and column 1:
[−1−123]
b21=(−1)(3)−(2)(−1)
b21=−3+2
b21=−1
For b22, delete row 2 and column 2:
[1223]
b22=(1)(3)−(2)(2)
b22=3−4
b22=−1
For b23, delete row 2 and column 3:
[12−1−1]
b23=(1)(−1)−(−1)(2)
b23=−1+2
b23=1
For b31, delete row 3 and column 1:
[−142−5]
b31=(−1)(−5)−(2)(4)
b31=5−8
b31=−3
For b32, delete row 3 and column 2:
[132−5]
b32=(1)(−5)−(2)(3)
b32=−5−6
b32=−11
For b33, delete row 3 and column 3:
[13−14]
b33=(1)(4)−(−1)(3)
b33=4+3
b33=7
Therefore, the matrix of minors is:
B=7−1−319−1−11−1117