Find the determinant of the matrix with rows (-2, -1) and (9, 9).
Answer and explanation
Correct answer: C.
- Step 1: For a 2×2 matrix the determinant is ad − bc. Step 2. (-2)(9) − (-1)(9) = -9. **Answer: . Why not the others:** is what you get if you add the products instead of subtracting. is what you get if you subtract in the wrong order. is what you get if you add and subtract the entries.
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