3. \( \left[\begin{array}{cc}1 & -2 \\ 3 & 4\end{array}\right] \times\left[\begin{array}{cc}0 & 2 \\ 1 & -1\end{array}\right] \)

It seems there was an error in the calculation. Let's try again. To calculate the product of two matrices, we need to follow the rules of matrix multiplication. The product of two matrices A and B is a matrix C, where each element of C is the dot product of a row of A and a column of B. Let's calculate the product of the given matrices step by step: 1. Multiply the first row of the first matrix by the first column of the second matrix: \(1 \times 0 + (-2) \times 1 = -2\) 2. Multiply the first row of the first matrix by the second column of the second matrix: \(1 \times 2 + (-2) \times (-1) = 4\) 3. Multiply the second row of the first matrix by the first column of the second matrix: \(3 \times 0 + 4 \times 1 = 4\) 4. Multiply the second row of the first matrix by the second column of the second matrix: \(3 \times 2 + 4 \times (-1) = 2\) Therefore, the product of the given matrices is: \[ \begin{bmatrix} -2 & 4 \\ 4 & 2 \end{bmatrix} \]