How to multiply a matrices 3x3 by 3x2

The top row of matrix A (1, 2, 1) is multiplied with the first column of matrix B (1,0,-1) and the result is 1x1 + 2x0 + 1x - 1 = 0 this is row 1 column 1 of the resultant matrix

The top row of matrix A (1,2,1) is multiplied with the second column of matrix B (-1, - 1, 1) and the result is 1 x-1 + 2 x - 1 + 1 x 1 = - 2, this is row 1 column 2 of the resultant matrix

Repeat with the second row of matrix A (-1,-1.-2) x (1,0,-1) = 1 this is row 2 column 1 of the resultant matrix, multiply the second row of A (-1,-1,-2) x (-1,-1,1) = 0, this is row 2 column 2 of the resultant

Repeat with the third row of matrix A (-1,1,-2) x (1,0, - 1) = 1, this is row 3 column 1 of the resultant

the third row of A (-1,1,-2) x (-1,-1,1) = - 2, this is row 3 column 2 of the resultant matrix

Matrix AB (0,-2/1,0/1,-2)