For the matrix equation $AX=B$, if $|A|\neq 0$, the unique solution is
- $X=AB$
- $X=A^{-1}$
- $X=A^{-1}B$
- $X=BA^{-1}$
Show answer and solution
Correct answer: C. $X=A^{-1}B$
When $|A|\neq 0$, the inverse $A^{-1}$ exists.
Pre-multiplying $AX=B$ by $A^{-1}$ gives $A^{-1}AX=A^{-1}B$, so $IX=A^{-1}B$, hence $X=A^{-1}B$.