If \( \begin{bmatrix}x+2y & -y\\3x & 4\end{bmatrix}=\begin{bmatrix}-4 & 3\\6 & 4\end{bmatrix} \), then \( 3x+2y \) is equal to
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 0
Equal matrices have equal corresponding entries:
\( \displaystyle 3x=6\;\Rightarrow\;x=2 \)
\( \displaystyle -y=3\;\Rightarrow\;y=-3 \)
These also satisfy the (1, 1) entry: x + 2y = 2 − 6 = −4.
\( \displaystyle 3x+2y=6-6=0 \)