Matrices Practice Questions Ques7
Question: If $A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$ and $B = \begin{pmatrix} 2 & 0 \\ 1 & 3 \end{pmatrix}$, what is $BA$?
Options:
(A) $\begin{pmatrix} 2 & 4 \\ 10 & 15 \end{pmatrix}$
(B) $\begin{pmatrix} 2 & 4 \\ 10 & 18 \end{pmatrix}$
(C) $\begin{pmatrix} 2 & 4 \\ 9 & 15 \end{pmatrix}$
(d) $\begin{pmatrix} 2 & 4 \\ 10 & 14 \end{pmatrix}$
Show Answer
Answer: D
Explanation:
(A) Incorrect. This is not the correct result of the matrix multiplication.
(B) Incorrect. This is not the correct result of the matrix multiplication.
(C) Incorrect. This is not the correct result of the matrix multiplication.
(D) Correct. Matrix multiplication is performed as follows: $\begin{pmatrix} 2 \cdot 1 + 0 \cdot 3 & 2 \cdot 2 + 0 \cdot 4 \\ 1 \cdot 1 + 3 \cdot 3 & 1 \cdot 2 + 3 \cdot 4 \end{pmatrix} = \begin{pmatrix} 2 & 4 \\ 10 & 14 \end{pmatrix}$.
BETA
