Question

Find the value of a,b,c, and d from the equation: $\begin{bmatrix}a-b&2a+c\\\2a-b&3c+d\end{bmatrix}=\begin{bmatrix}-1&5\\\0&13\end{bmatrix}$

Answer 1

$\begin{bmatrix}a-b&2a+c\\\2a-b&3c+d\end{bmatrix}=\begin{bmatrix}-1&5\\\0&13\end{bmatrix}$As the two matrices are equal, their corresponding elements are also equal.
Comparing the corresponding elements, we get:
a − b = −1 … (1)
2a − b = 0 … (2)
2a + c = 5 … (3)
3c + d = 13 … (4)
From (2), we have:
b = 2a
Then, from (1), we have:
a − 2a = −1
$\Rightarrow$ a = 1
$\Rightarrow$b = 2
Now, from (3), we have:
2 ×1 + c = 5
$\Rightarrow$ c = 3
From (4) we have:
3 ×3 + d = 13
$\Rightarrow$ 9 + d = 13 ⇒ d = 4

∴a = 1, b = 2, c = 3, and d = 4