If A = [[1, 0], [0, -1]] and B = [[0, 1], [1, 0]], then AB is equal to:

If A = [[1, 0], [0, -1]] and B = [[0, 1], [1, 0]], then AB is equal to:

• A. [[0, 1], [-1, 0]]
• B. [[0, -1], [1, 0]]
• C. [[1, 0], [0, 1]]
• D. [[0, 0], [0, 0]]

Answer: A) [[0, 1], [-1, 0]]

Explanation: Multiplying rows of A with columns of B: element(1,1) = (1×0)+(0×1)=0, element(1,2) = (1×1)+(0×0)=1, element(2,1) = (0×0)+(−1×1)=−1, element(2,2) = (0×1)+(−1×0)=0. Result is [[0, 1], [-1, 0]].