Aside from the fact that im a complete retard when it comes to math my teacher is also horrendous....Any help with these problems would be much appreciated!..

if A=[3 6] [-1 5]
[1 2] and B= [4 3] then find A-2B

Find the matrix....[1 2] [4 1 1]
[-1 3] [1 2 3]
[1 1]

2. Originally Posted by JP101
Aside from the fact that im a complete retard when it comes to math my teacher is also horrendous....Any help with these problems would be much appreciated!..

if A=[3 6] [-1 5]
[1 2] and B= [4 3] then find A-2B

Find the matrix....[1 2] [4 1 1]
[-1 3] [1 2 3]
[1 1]
For the first one, the components for 2B are just $2[b_{ij}]$ so the the components of C = A - 2B are just $c_{ij} = a_{ij} - 2b_{ij}$.

For the second one I presume you know how to multiply matrices? If we have C = AB then $c_{ik} = \sum_j a_{ij}b_{jk}$.

Try those formulas out and see what you get. Come back if you are still confused.

-Dan