Answer:
A Matrix is an array of numbers:
2x3 Matrix
A Matrix
(This one has 2 Rows and 3 Columns)
To multiply a matrix by a single number is easy:
Matrix Multiply Constant
These are the calculations:
2×4=8 2×0=0
2×1=2 2×-9=-18
We call the number ("2" in this case) a scalar, so this is called "scalar multiplication".