Question 205232
A={{{(
matrix(2,3,
2,3,6,
4,-2,0)
)}}}
2A={{{2*(
matrix(2,3,
2,3,6,
4,-2,0)
)=(
matrix(2,3,
2*2,2*3,2*6,
2*4,2*(-2),2*0)
)=(
matrix(2,3,
4,6,12,
8,-4,0)
)}}}


B={{{(
matrix(3,3,
1,0,1,
0,1,0,
2,1,0)
)}}}
2B={{{2*(
matrix(3,3,
1,0,1,
0,1,0,
2,1,0)
)=(
matrix(3,3,
2*1,2*0,2*1,
2*0,2*1,2*0,
2*2,2*1,2*0)
)=(
matrix(3,3,
2,0,2,
0,2,0,
4,2,0)
)}}}


2A*B={{{(
matrix(2,3,
4,6,12,
8,-4,0)
)*(
matrix(3,3,
1,0,1,
0,1,0,
2,1,0)
)
}}}
={{{(matrix(2,3,
4*1+6*0+12*2, 4*0+6*1+12*1, 4*1+6*0+12*0,
8*1+(-4)*0+0*2, 8*0+(-4)*1+0*1, 8*1+(-4)*0+0*0))}}}
={{{(matrix(2,3,
4+0+24, 0+6+12, 4+0+0,
8+0+0,0-4+0, 8+0+0))}}}
={{{(matrix(2,3,
28, 18, 4,
8,-4, 8))}}}


2 matrices can be multiplied if number of columns in 1st matrix = number of rows in 2nd matrix
so, there is no results for 2B*A because there are 3 columns in matrix 2B and there are 2 rows in matrix A