How many solutions does the system $2x + 3y = 5$, $4x + 6y = 10$ have?

Explanation

1. 01

   $|A| = 0$. It is 0, so look at $(\operatorname{adj} A)B$.

2. 02

   $(\operatorname{adj} A)B = \begin{bmatrix}0 \\ 0\end{bmatrix}$. It is zero, so the equations say the same thing: infinitely many solutions.