Question

Find the adjoint of[2 1 1
0 2 1
0 0 2]

Answer 1

Answer:

adjoint=[4 -2 -1

0 4 -2

0 0 4].

Step-by-step explanation:

Let A=[2 1 1

0 2 1

0 0 2]

M11=4, A11=4

M12=0, A12=0

M13=0, A13=0

M21=2, A21=-2

M22=4, A22=4

M23=0, A23=0

M31=-1, A31=-1

M32=2, A32=-2

M33=4, A33=4

the cofactor matrix =[4 0 0

-2 4 0

-1 -2 4]

hence the adjoint =[4 -2 -1

0 4 -2

0 0 4].