Random
Addition and Subtraction
Matrix Multiplication
Inverses
Systems of Equations
100

What the the order of the matrix

2x3

100

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)

100

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.

100

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]]

100

When will a system of equations have no solutions?

When the determinant = 0 (i.e. it is not possible to find an inverse)

200

Identify element a23 from A =

2

200

Find A - B:

A = [[2,-3],[-1,4]]

B=[[-4,1],[3,-2]]

A-B=[[-6,4],[4,-6]]

200

Multiply A and B.

A=[[1,1],[1,1]]

B=[[0,3],[4,4]]

AB=[[4,7],[4,7]]

200

Determine if these two matrices are inverses:

A=[[-9,-4],[-5,-2]]

B=[[1,-2],[-5/2,9/2]]

Yes, they are!

200

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]]

300

Identify

1. 2x2 identity matrix

2. 3x3 identity matrix

1. [[1,0],[0,1]]

2.[[1,0,0],[0,1,0],[0,0,1]]

300

Find B - A

[[0,4,1],[2,-3,0],[6,6,-2]]

300

Multiply:

[[1,2, -2, -1],[-3, -4, 4, 3]]  [[5],[6],[7],[8]] 

[[-5],[13]] 

300

Find the determinant of A:

A=[[3, 3],[-1, -1]]

det(A) = 0

300

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

400

Do the following, and determine a13 of result:

[[-25,-30,20],[-20,10,5]]

a13 = 20

400

Find -1/3 B - A 

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

400

Multiply:

[[-12,-3,-6,12,6],[4,-4,0,0,0]]

400

If possible, find the inverse of A:

A=[[2,6],[-1,-5]]

A^-1=[[5/4,3/2],[-1/4,-1/2]]

400

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

500

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.

500

Find  2A-1/6 B 

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

500

Multiply:

[[6,-8,2],[7,-5,11],[-2,6,-10]]

500

If possible, find the inverse of A:

A=[[3, 4],[-2, -1]]

A^-1=[[-1/5, -4/5],[2/5, 3/5]]

500

Solve using inverse matrices, expressing your answers to 3 significant figures:

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