#### Please Solve RD Sharma Class 12 Chapter Algebra of Matrices Exercise 4.2 Question 3 Suquestion (ii) Maths Textbook Solution.

Answer: $\begin{bmatrix} 1 & 6 &1 \\ -6& -13 & -4 \end{bmatrix}$
Hint: $2B + 3A$ don’t exist because the number of elements in A are not equal to the number of elements in B or we can say, the order of matrices is not equal.

Given: $A= \begin{bmatrix} 2 &3 \\ 5 &7 \end{bmatrix}$ , $B= \begin{bmatrix} -1 &0 &2 \\ 3& 4 &1 \end{bmatrix}$  and $C= \begin{bmatrix} -1 & 2& 3\\ 2 &1 &0 \end{bmatrix}$

Here, we have to compute $2B + 3A$  and $3C - 4B.$
Solution:
$2B + 3A$  don’t exist because the no. of rows and columns of both the matrices are not same.

$3C - 4B=3\begin{bmatrix} -1 & 2 & 3\\ 2 & 1 & 0 \end{bmatrix}-4\begin{bmatrix} -1 &0 &2 \\ 3 & 4 &1 \end{bmatrix}$

$=\begin{bmatrix} -3 & 6 & 9\\ 6 & 3 & 0 \end{bmatrix}-\begin{bmatrix} -4 &0 &8 \\ 12 & 16 &4 \end{bmatrix}$

$=\begin{bmatrix} -3+4 & 6-0 & 9-8\\ 6-12 & 3-16 & 0 -4\end{bmatrix}$

$=\begin{bmatrix} 1 & 6 & 1\\ -6 & -13 & -4\end{bmatrix}$