$A = [a_{ij}]$ is a 2 × 3 matrix with $a_{ij} = i + 2j$. What is $a_{23}$?

Explanation

1. 01

   In $a_{23}$, $i = 2$ is the row and $j = 3$ the column.

2. 02

   $a_{23} = 2 + 2(3) = 8$.