If A has rows (3, 3) and (-3, 2) and B has rows (3, -3) and (-1, 1), find the entry in row 1, column 2 of AB.
Answer and explanation
Correct answer: A.
- Step 1: The entry is (row 1 of A) · (column 2 of B). Step 2. (3)(-3) + (3)(1) = -6. **Answer: . Why not the others:** is what you get if you multiply the entries by rows of B instead of columns. is what you get if you multiply the matching entries. does not fit.
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