Question

If A = $\left[\begin{array}{ccc}1& 4& 5\\ 3& 2& 6\end{array}\right]$ then second element of second row of 3A = _____.

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Answer 1

Here A = $\left[\begin{array}{ccc}1& 4& 5\\ 3& 2& 6\end{array}\right]$ so 3A will be obtained by multiplying every element of A by 3.

So $3A=\left[\begin{array}{ccc}3\times 1& 3\times 4& 3\times 5\\ 3\times 3& 3\times 2& 3\times 6\end{array}\right]$

$=\left[\begin{array}{ccc}3& 12& 15\\ 9& 6& 18\end{array}\right]$ So the second element of second row of this matrix will be 6, which is the correct answer.