The correct option is C If M⎡⎢⎣αβγ⎤⎥⎦=⎡⎢⎣123⎤⎥⎦,then α−β+γ=3
(adj M)11=∣∣∣23b1∣∣∣=−1
⇒2−3b=−1 ⇒b=1
(adj M)22=∣∣∣0a31∣∣∣=−6
⇒−3a=−6 ⇒a=2
so, a+b=2+1=3
Therefore,M=⎡⎢⎣012123311⎤⎥⎦
det M=0+−1(1−9)+2(1−6)=−2
|adj (M2)|=|M2|2=|M|4=(−2)4=16
∵M−1=adj Mdet M=adj M−2
so, (adj M)−1+adj M−1
(M−1|M|)−1+(M−1)−1|M−1|
(M−1)−1|M|+M|M|
M−2+M−2=−M
∴(adj M)−1+adj M−1=−M
If M⎡⎢⎣αβγ⎤⎥⎦=⎡⎢⎣123⎤⎥⎦
As, MX=B⇒X=M−1B=adj M|M|.B
=−12⎡⎢⎣−11−18−62−53−1⎤⎥⎦⎡⎢⎣123⎤⎥⎦=⎡⎢⎣1−11⎤⎥⎦
X=⎡⎢⎣1−11⎤⎥⎦=⎡⎢⎣αβγ⎤⎥⎦
∴(α,β,γ)=(1,−1,1)
Hence, (α−β+γ)=3