$\begin{bmatrix} a-b & 2a+c \\ 2a-b & 3c+d \end{bmatrix}$ = $\begin{bmatrix} -1 & 5 \\ 0 & 13 \end{bmatrix}$ Equating the corresponding elements, we get, ⇒ a - b = -1, 2a + c = 5, 2a - b = 0, 3c + d = 13 Now, consider the equations: a - b = -1 and 2a - b = 0 Subtracting first equation from second, we get: a = 1