PLS HELP!! Algebra 2, matrices

Question

If A=[2 8 3] [-1 0 5]

[-1 5 2]and B=[0 3 -2], what is 4A+3B? Solve algebraically, showing all steps.

Answer 1

Hi Jordan,

When multiplying a matrix by a scalar, you just need to multiply each term in the matrix by. that scalar So, for the first matrix, to get 4A:

4[2 8 3

-1 5 2]=

[8 32 12

-4 20 8]

Now do the same with 3B:

3[-1 0 5

0 3 -2]=

[-3 0 15

0 9 -6]

When we add matrices, we simply add the individual terms, so:

[8 32 12 [-3 0 15

-4 20 8] + 0 9 -6] =

[5 32 27

-4 29 2]

Keep in mind that we need the same dimensions--ex. 2*3 here--in both matrices in order to add matrices together. I hope this helps.