If $P=\left[\begin{array}{r}-1 \\ 2 \\ 1\end{array}\right]$ and $Q=\left[\begin{array}{lll}2 & -4 & 1\end{array}\right]$ are two matrices, then $(PQ)'$ will be:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → $\left[\begin{array}{rrr}-2 & 4 & 2 \\ 4 & -8 & -4 \\ -1 & 2 & 1\end{array}\right]$
$(PQ)^T$
$=Q^TP^T$
$=\begin{bmatrix}2\\-4\\1\end{bmatrix}\begin{bmatrix}-1&2&1\end{bmatrix}$
$=\begin{bmatrix}-2&4&2\\4&-8&-4\\-1&2&1\end{bmatrix}$