2. Two marks example problems I

1. If \(A =\) $\left(\begin{array}{lll}1& 2& 3\\ 4& 5& 6\\ 7& 8& 9\end{array}\right)$, \(B =\) $\left(\begin{array}{lll}1& 7& 0\\ 1& 3& 1\\ 2& 4& 0\end{array}\right)$, find \(A + B\).

 

Answer:

 

\(A + B\) \(=\) $\left(\begin{array}{lll}i& i& i\\ i& i& i\\ i& i& i\end{array}\right)$

 

 

2. Two examinations were conducted for three groups of students, namely group \(1\), group \(2\), and group \(3\) and their data on average of marks for the subjects Tamil, English, Science and Mathematics are given below in the form of matrices \(A\) and \(B\). First, find the total marks of both the examinations for all the three groups.

 

 

 

Answer:

 

The total marks of both the groups \(=\) $\left(\begin{array}{llll}i& i& i& i\\ i& i& i& i\\ i& i& i& i\end{array}\right)$

 

 

3. If \(A =\) $\left(\begin{array}{lll}7& 8& 6\\ 1& 3& 9\\ -4& 3& -1\end{array}\right)$, \(B =\) $\left(\begin{array}{lll}4& 11& -3\\ -1& 2& 4\\ 7& 5& 0\end{array}\right)$ then find \(2A + B\).