My advice:
- Learn how to multiply a matrix M by a column vector v.
- Generalise that by noticing that M[u|v|...] = [Mu|Mv|...].
That's matrix multiplication.
- Learn how to multiply a matrix M by a column vector v.
- Generalise that by noticing that M[u|v|...] = [Mu|Mv|...].
That's matrix multiplication.