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Math Gym
Determinants Guide

Determinants Level 19: 3x3 triangular realistic (no timer). 3x3 cofactor boxes.

1. First cofactor box

1. First cofactor box
Show the first entry times its 2x2 minor.

2. Second cofactor box

2. Second cofactor box
Settle box 1; show the next 2x2 minor.

3. Third cofactor box

3. Third cofactor box
Settle box 2; show the final 2x2 minor.

4. Add three boxes

4. Add three boxes
Add the three signed box values.