Algebra 1

$[1 1 1 ] + [2 3 4]$ $[1 1 1 ] + [5 6 7]$ $[1 1 1] + [8 9 10]$ The three elements of the first row are added to each other. $1+2=3$ $1+3=4$ $1+4=5$ The three elements of the second row are added to each other. $1+5=6$ $1+6=7$ $1+7=8$ The three elements of the third row are added to each other. $1+8=9$ $1+9=10$ $1+10=11$ Resulting matrix: $[3 4 5]$ $[6 7 8]$ $[9 10 11]$