[tex]\longrightarrow[/tex]In a matrix the the the position of an element is determined by using a[tex]_{ij}[/tex] where i the number of row and j is number of column in which the element is.
[tex]\leadsto[/tex]Since 6 is in 2nd column and 2nd row , it's position can be written as a[tex]_{22}[/tex]
Comparing with a[tex]_{ij}[/tex]