Solve this

Question:

If $\left[\begin{array}{cc}a+4 & 3 b \\ 8 & -6\end{array}\right]=\left[\begin{array}{cc}2 a+2 & b+2 \\ 8 & a-8 b\end{array}\right]$, write the value of $a-2 b$.

Solution:

$\left[\begin{array}{cc}a+4 & 3 b \\ 8 & -6\end{array}\right]=\left[\begin{array}{cc}2 a+2 & b+2 \\ 8 & a-8 b\end{array}\right]$

Corresponding elements of equal matrices are equal.

$\therefore a+4=2 a+2 \quad$ and $\quad 3 b=b+2$

$\Rightarrow 4-2=2 a-a \quad$ and $\quad 3 b-b=2$

$\Rightarrow a=2 \quad$ and $\quad 2 b=2$

$\Rightarrow a=2 \quad$ and $\quad b=1$

$\therefore a-2 b=2-2=0$

Leave a comment

Close

Click here to get exam-ready with eSaral

For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.

Download Now