Question

Solve for x and y:
$\left[\begin{array}{cc}-2& 0\\ 3& 1\end{array}\right]\left[\begin{array}{c}-1\\ 2x\end{array}\right]+3\left[\begin{array}{c}-2\\ 1\end{array}\right]=2\left[\begin{array}{c}y\\ 3\end{array}\right]$

• A. 3, 2
• B. 3, -2
• C. -3, 2
• D. -3, -2

Answer 1

Answer: (B)

3, -2

$\left[\begin{array}{cc}-2& 0\\ 3& 1\end{array}\right]\left[\begin{array}{c}-1\\ 2x\end{array}\right]+3\left[\begin{array}{c}-2\\ 1\end{array}\right]=2\left[\begin{array}{c}y\\ 3\end{array}\right]$

$\left[\begin{array}{c}2\\ -3+2x\end{array}\right]+\left[\begin{array}{c}-6\\ 3\end{array}\right]=\left[\begin{array}{c}2y\\ 6\end{array}\right]$

$\therefore 2y=2-6$
$y=-2$
$-3+2x+3=6$
$x=3$