1. Write your 3 x 3 matrix. More ↓ 2. Choose a single row or column. ↓ 3. Cross out the row and column of your first element. ↓ 4. Find the determinant of the 2 x 2 matrix. ↓ 5. Multiply the answer by your chosen element. ↓ 6. Determine the sign of your answer. ↓ 7. Repeat this process for the second element in your reference row or column. ↓ 8. Repeat with the third element. ↓ 9. Add your three results together. ↓
