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Determinants

Level 14 / mastery

3x3 (+/-6)

3 visual steps / 3x3 signed cofactors

1. Signed line

1. Signed linerow 1 signs + - +.2-3140-2-153row 1 signs + -+terms 20 + 30 +20det = 70
row 1 signs + - +.

row 1 signs + - +.

2. Signed term

2. Signed termterms 20 + 30 + 20.2-3140-2-153row 1 signs + -+terms 20 + 30 +20det = 70
terms 20 + 30 + 20.

terms 20 + 30 + 20.

3. Determinant

3. Determinantdet = 70.DeterminantSettle signed terms.det = 70.terms 20 + 30 + 20
det = 70.

det = 70.

Practice Level 14

A few quick rounds make the products familiar; the sign is the only thing to guard.

Start Level