MCQ
If $\left[\begin{array}{cc}x+2 y & 3 y \\ 4 x & 2\end{array}\right]=\left[\begin{array}{cc}0 & -3 \\ 8 & 2\end{array}\right]$ then the value of $x-y$ is
- A$-3$
- B1
- ✓3
- D5
✓
Answer
Correct option: C.
3
$
\left[\begin{array}{cc}
x+2 y & 3 y \\
4 x & 2
\end{array}\right]=\left[\begin{array}{cc}
0 & -3 \\
8 & 2
\end{array}\right]
$
Comparing, we get
$
\begin{aligned}
& 3 y=-3 \\
& \Rightarrow y=\frac{-3}{3}=-1 \\
& 4 x=8 \\
& \Rightarrow x=\frac{8}{4}=2 \\
& x-y=2-(-1) \\
& =2+1 \\
& =3
\end{aligned}
$
\left[\begin{array}{cc}
x+2 y & 3 y \\
4 x & 2
\end{array}\right]=\left[\begin{array}{cc}
0 & -3 \\
8 & 2
\end{array}\right]
$
Comparing, we get
$
\begin{aligned}
& 3 y=-3 \\
& \Rightarrow y=\frac{-3}{3}=-1 \\
& 4 x=8 \\
& \Rightarrow x=\frac{8}{4}=2 \\
& x-y=2-(-1) \\
& =2+1 \\
& =3
\end{aligned}
$
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