Row Operations for Finding Inverse of Matrix (3x3) (Level 1)

This math topic focuses on manipulating 3x3 matrices to find their inverses using elementary row operations. Skills practiced include adding and subtracting rows, multiplying rows by constants, and row swapping. Each problem provides an augmented matrix with various objectives, such as solving for specific rows of the inverse matrix. Multiple-choice answers with LaTex-rendered matrix options guide learners to practice and reinforce these algebraic techniques systematically.

Work on practice problems directly here, or download the printable pdf worksheet to practice offline.

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Row Operations for Finding Inverse of Matrix (3x3)

Complete these online problems with 80% or 4 correct answers in a row. Results are immediate.


Multiply row 3 of the augmented matrix by whatever factor is needed to solve for that row of the inverse matrix

[411100659010000.25001]\left[ {\begin{array} {cccc} 4 & 1 & 1 & \vert & 1 & 0 & 0 \\ 6 & 5 & 9 & \vert & 0 & 1 & 0 \\ 0 & 0 & 0.25 & \vert & 0 & 0 & 1 \end{array} } \right]

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Matrices - Row Operations for Finding Inverse of Matrix (3x3) Worksheet

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Math worksheet on 'Matrices - Row Operations for Finding Inverse of Matrix (3x3) (Level 1)'. Part of a broader unit on 'Matrices' Learn online: app.mobius.academy/math/units/matrices/
1
Multiply row 3 of the augmented matrix by whatever factor is needed to solve for that row of the inverse matrix
A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 5 & 5 & \vert & 1 & 0 & 0 \\ 6 & 5 & 3 & \vert & 0 & 1 & 0 \\ 0 & 0 & 0.25 & \vert & 0 & 0 & 1 \end{array} } \right]
a A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 5 & 5 & \vert & 1 & 0 & 0 \\ 6 & 5 & 3 & \vert & 0 & 1 & 0 \\ 0 & 0 & 0.06 & \vert & 0 & 0 & 6 \end{array} } \right]
b A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 5 & 5 & \vert & 1 & 0 & 0 \\ 6 & 5 & 3 & \vert & 0 & 1 & 0 \\ 0 & 0 & 0.06 & \vert & 0 & 0 & -2 \end{array} } \right]
c A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 5 & 5 & \vert & 1 & 0 & 0 \\ 6 & 5 & 3 & \vert & 0 & 1 & 0 \\ 0 & 0 & 0.06 & \vert & 0 & 0 & 5 \end{array} } \right]
d A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 5 & 5 & \vert & 1 & 0 & 0 \\ 6 & 5 & 3 & \vert & 0 & 1 & 0 \\ 0 & 0 & 1 & \vert & 0 & 0 & 4 \end{array} } \right]
e A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 5 & 5 & \vert & 1 & 0 & 0 \\ 6 & 5 & 3 & \vert & 0 & 1 & 0 \\ 0 & 0 & 0.06 & \vert & 0 & 0 & 3 \end{array} } \right]
f A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 5 & 5 & \vert & 1 & 0 & 0 \\ 6 & 5 & 3 & \vert & 0 & 1 & 0 \\ 0 & 0 & 0.06 & \vert & 0 & 0 & 7 \end{array} } \right]
2
Multiply row 2 of the augmented matrix by whatever factor is needed to solve for that row of the inverse matrix
A LaTex expression showing \left[ {\begin{array} {cccc} 5 & 6 & 9 & \vert & 1 & 0 & 0 \\ 0 & 0.33 & 0 & \vert & 0 & 1 & 0 \\ 9 & 7 & 6 & \vert & 0 & 0 & 1 \end{array} } \right]
a A LaTex expression showing \left[ {\begin{array} {cccc} 5 & 6 & 9 & \vert & 1 & 0 & 0 \\ 0 & 0.11 & 0 & \vert & 0 & 2.25 & 0 \\ 9 & 7 & 6 & \vert & 0 & 0 & 1 \end{array} } \right]
b A LaTex expression showing \left[ {\begin{array} {cccc} 5 & 6 & 9 & \vert & 1 & 0 & 0 \\ 0 & 0.11 & 0 & \vert & 0 & 5.25 & 0 \\ 9 & 7 & 6 & \vert & 0 & 0 & 1 \end{array} } \right]
c A LaTex expression showing \left[ {\begin{array} {cccc} 5 & 6 & 9 & \vert & 1 & 0 & 0 \\ 0 & 0.11 & 0 & \vert & 0 & -2.25 & 0 \\ 9 & 7 & 6 & \vert & 0 & 0 & 1 \end{array} } \right]
d A LaTex expression showing \left[ {\begin{array} {cccc} 5 & 6 & 9 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 3 & 0 \\ 9 & 7 & 6 & \vert & 0 & 0 & 1 \end{array} } \right]
e A LaTex expression showing \left[ {\begin{array} {cccc} 5 & 6 & 9 & \vert & 1 & 0 & 0 \\ 0 & 0.11 & 0 & \vert & 0 & 3.75 & 0 \\ 9 & 7 & 6 & \vert & 0 & 0 & 1 \end{array} } \right]
f A LaTex expression showing \left[ {\begin{array} {cccc} 5 & 6 & 9 & \vert & 1 & 0 & 0 \\ 0 & 0.11 & 0 & \vert & 0 & 1.5 & 0 \\ 9 & 7 & 6 & \vert & 0 & 0 & 1 \end{array} } \right]
3
Swap rows 1 and 2 of the augmented matrix to solve those rows of the inverse matrix
A LaTex expression showing \left[ {\begin{array} {cccc} 0 & 1 & 0 & \vert & 1 & 0 & 0 \\ 1 & 0 & 0 & \vert & 0 & 1 & 0 \\ 7 & 7 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
a A LaTex expression showing \left[ {\begin{array} {cccc} 1 & 0 & 0 & \vert & 0 & 1 & 0 \\ 0 & 1 & 0 & \vert & 1 & 0 & 0 \\ 7 & 7 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
b A LaTex expression showing \left[ {\begin{array} {cccc} 1 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & 0 \\ 7 & 7 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
c A LaTex expression showing \left[ {\begin{array} {cccc} 1 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 1 & 0 & 0 \\ 7 & 7 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
d A LaTex expression showing \left[ {\begin{array} {cccc} 1 & 0 & 0 & \vert & 0 & 0 & 1 \\ 0 & 1 & 0 & \vert & 0 & 1 & 0 \\ 7 & 7 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
e A LaTex expression showing \left[ {\begin{array} {cccc} 1 & 0 & 0 & \vert & 0 & 1 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & 0 \\ 7 & 7 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
f A LaTex expression showing \left[ {\begin{array} {cccc} 1 & 0 & 0 & \vert & 0 & 0 & 1 \\ 0 & 1 & 0 & \vert & 0 & 0 & 1 \\ 7 & 7 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
4
Divide row 3 of the augmented matrix by whatever factor is needed to solve for that row of the inverse matrix
A LaTex expression showing \left[ {\begin{array} {cccc} 3 & 7 & 2 & \vert & 1 & 0 & 0 \\ 8 & 8 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 4 & \vert & 0 & 0 & 1 \end{array} } \right]
a A LaTex expression showing \left[ {\begin{array} {cccc} 3 & 7 & 2 & \vert & 1 & 0 & 0 \\ 8 & 8 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 16 & \vert & 0 & 0 & -6 \end{array} } \right]
b A LaTex expression showing \left[ {\begin{array} {cccc} 3 & 7 & 2 & \vert & 1 & 0 & 0 \\ 8 & 8 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 16 & \vert & 0 & 0 & 3 \end{array} } \right]
c A LaTex expression showing \left[ {\begin{array} {cccc} 3 & 7 & 2 & \vert & 1 & 0 & 0 \\ 8 & 8 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 1 & \vert & 0 & 0 & 0.25 \end{array} } \right]
d A LaTex expression showing \left[ {\begin{array} {cccc} 3 & 7 & 2 & \vert & 1 & 0 & 0 \\ 8 & 8 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 16 & \vert & 0 & 0 & 6 \end{array} } \right]
e A LaTex expression showing \left[ {\begin{array} {cccc} 3 & 7 & 2 & \vert & 1 & 0 & 0 \\ 8 & 8 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 16 & \vert & 0 & 0 & -3 \end{array} } \right]
f A LaTex expression showing \left[ {\begin{array} {cccc} 3 & 7 & 2 & \vert & 1 & 0 & 0 \\ 8 & 8 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 16 & \vert & 0 & 0 & -4 \end{array} } \right]
5
Add row 1 to row 2 of the augmented matrix as many times as needed to solve for row 2 of the inverse matrix
A LaTex expression showing \left[ {\begin{array} {cccc} 4 & 0 & 0 & \vert & 1 & 0 & 0 \\ -8 & 1 & 0 & \vert & 0 & 1 & 0 \\ 1 & 7 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
a A LaTex expression showing \left[ {\begin{array} {cccc} 4 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & -3 & 1 & 0 \\ 1 & 7 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
b A LaTex expression showing \left[ {\begin{array} {cccc} 4 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 1 & 1 & 0 \\ 1 & 7 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
c A LaTex expression showing \left[ {\begin{array} {cccc} 4 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & -6 & 1 & 0 \\ 1 & 7 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
d A LaTex expression showing \left[ {\begin{array} {cccc} 4 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 6 & 1 & 0 \\ 1 & 7 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
e A LaTex expression showing \left[ {\begin{array} {cccc} 4 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 2 & 1 & 0 \\ 1 & 7 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
f A LaTex expression showing \left[ {\begin{array} {cccc} 4 & 0 & 0 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 4 & 1 & 0 \\ 1 & 7 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
6
Add row 3 to row 2 of the augmented matrix as many times as needed to solve for row 2 of the inverse matrix
A LaTex expression showing \left[ {\begin{array} {cccc} 9 & 3 & 2 & \vert & 1 & 0 & 0 \\ 0 & 1 & -9 & \vert & 0 & 1 & 0 \\ 0 & 0 & 3 & \vert & 0 & 0 & 1 \end{array} } \right]
a A LaTex expression showing \left[ {\begin{array} {cccc} 9 & 3 & 2 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & -6 \\ 0 & 0 & 3 & \vert & 0 & 0 & 1 \end{array} } \right]
b A LaTex expression showing \left[ {\begin{array} {cccc} 9 & 3 & 2 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & 9 \\ 0 & 0 & 3 & \vert & 0 & 0 & 1 \end{array} } \right]
c A LaTex expression showing \left[ {\begin{array} {cccc} 9 & 3 & 2 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & -3 \\ 0 & 0 & 3 & \vert & 0 & 0 & 1 \end{array} } \right]
d A LaTex expression showing \left[ {\begin{array} {cccc} 9 & 3 & 2 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & -4.5 \\ 0 & 0 & 3 & \vert & 0 & 0 & 1 \end{array} } \right]
e A LaTex expression showing \left[ {\begin{array} {cccc} 9 & 3 & 2 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & 10.5 \\ 0 & 0 & 3 & \vert & 0 & 0 & 1 \end{array} } \right]
f A LaTex expression showing \left[ {\begin{array} {cccc} 9 & 3 & 2 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & 3 \\ 0 & 0 & 3 & \vert & 0 & 0 & 1 \end{array} } \right]
7
Swap rows 2 and 3 of the augmented matrix to solve those rows of the inverse matrix
A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 1 & 5 & \vert & 1 & 0 & 0 \\ 0 & 0 & 1 & \vert & 0 & 1 & 0 \\ 0 & 1 & 0 & \vert & 0 & 0 & 1 \end{array} } \right]
a A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 1 & 5 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 0 & 1 \\ 0 & 0 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]
b A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 1 & 5 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 0 & 1 \\ 0 & 0 & 1 & \vert & 0 & 1 & 0 \end{array} } \right]
c A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 1 & 5 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 0 & 1 \\ 0 & 0 & 1 & \vert & 1 & 0 & 0 \end{array} } \right]
d A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 1 & 5 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 1 & 0 & 0 \\ 0 & 0 & 1 & \vert & 0 & 1 & 0 \end{array} } \right]
e A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 1 & 5 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 1 & \vert & 1 & 0 & 0 \end{array} } \right]
f A LaTex expression showing \left[ {\begin{array} {cccc} 7 & 1 & 5 & \vert & 1 & 0 & 0 \\ 0 & 1 & 0 & \vert & 0 & 1 & 0 \\ 0 & 0 & 1 & \vert & 0 & 0 & 1 \end{array} } \right]