What the the order of the matrix

2x3
What is the rule for determining if two matrices can be added or subtracted together?
The matrices have to be the exact same order (equal number of rows and columns)
If you are able, how do you multiply matrices?
You multiply each row in the first matrix by each column in the second matrix and then add each of those products together to get each individual element in the solution matrix.
What is the formula for finding the inverse of a 2x2 matrix:
A=[[a,b],[c,d]]
A^-1=1/(ad-bc)[[d,-b],[-c,a]]
When will a system of equations have no solutions?
When the determinant = 0 (i.e. it is not possible to find an inverse)
Identify element a23 from A =

2
Find A - B:
A = [[2,-3],[-1,4]]
B=[[-4,1],[3,-2]]
A-B=[[-6,4],[4,-6]]
Multiply A and B.
A=[[1,1],[1,1]]
B=[[0,3],[4,4]]
AB=[[4,7],[4,7]]
Determine if these two matrices are inverses:
A=[[-9,-4],[-5,-2]]
B=[[1,-2],[-5/2,9/2]]
Yes, they are!
Write a matrix to represent the following network:

[[0,1,1,1,0],[1,0,1,0,1],[1,1,0,0,1],[1,0,0,0,0],[0,1,1,0,0]]
Identify
1. 2x2 identity matrix
2. 3x3 identity matrix
1. [[1,0],[0,1]]
2.[[1,0,0],[0,1,0],[0,0,1]]
Find B - A

[[0,4,1],[2,-3,0],[6,6,-2]]
Multiply:
[[1,2, -2, -1],[-3, -4, 4, 3]] [[5],[6],[7],[8]]
[[-5],[13]]
Find the determinant of A:
A=[[3, 3],[-1, -1]]
det(A) = 0
Solve these simultaneous equations using matrix inverses, expressing your answers to 4 decimal places:
6x - 3y = -1
8x - 5y = -2
x=0.1667 and y=0.6667
Do the following, and determine a13 of result:

[[-25,-30,20],[-20,10,5]]
a13 = 20
Find -1/3 B - A

[[4,12,-8],[23,-17,12],[-1,10,-6]]
Multiply:

[[-12,-3,-6,12,6],[4,-4,0,0,0]]
If possible, find the inverse of A:
A=[[2,6],[-1,-5]]
A^-1=[[5/4,3/2],[-1/4,-1/2]]
Solve these simultaneous equations using inverse matrices, expressing your answers as fractions:
-4x - 7y = 2
5x - y = 7
x=47/39 and y=-38/39
Can the following matrices be multiplied together? If so, what would the size of the solution matrix be? If not, explain why not?
[[1,2],[3, 4],[5, 6]] [[1,2, 3],[4, 5, 6]]
Yes, because the first matrix is a 3x2, and the second matrix is a 2x3. Since the second matrix has the same number of rows, as the first one has columns (2), these matrices can be multiplied together. Their product matrix would have 3 rows and 3 columns.
Find 2A-1/6 B

[[2,3],[-11,7],[-18,-20],[-3,18]]
Multiply:

[[6,-8,2],[7,-5,11],[-2,6,-10]]
If possible, find the inverse of A:
A=[[3, 4],[-2, -1]]
A^-1=[[-1/5, -4/5],[2/5, 3/5]]
Solve using inverse matrices, expressing your answers to 3 significant figures:

x=-0.714 , y=4.86 , and z=-0.714