Which one of the following options is incorrect?
For a square matrix A in the matrix equation AX = B.
Answer & explanation
Correct answer: option 3
for AX = B
1 → |A| $\neq 0 \Rightarrow$ unique soln → correct
2 →|A| = 0 (Adj } A) B \neq 0 \Rightarrow$ no solution → correct
3 → |A| $neq 0$ (Adj A) B $\neq 0 \Rightarrow$ no solution → incorrect
4 → |A| = 0 $\Rightarrow$ (adj A)B = 0 $\Rightarrow$ infinite soln → correct