If `A=[(2,3),(-1,4)]`, find 4 A.

Answer

To find \( 4A \) for the matrix \( A = \begin{pmatrix} 2 & 3 \\ -1 & 4 \end{pmatrix} \), we will multiply each element of the matrix \( A \) by the scalar \( 4 \).

### Step-by-Step Solution:

1. **Identify the matrix \( A \)**:
\[ A = \begin{pmatrix} 2 & 3 \\ -1 & 4 \end{pmatrix} \]

2. **Multiply each element of the matrix by \( 4 \)**:
- For the element in the first row, first column:
\[ 4 \times 2 = 8 \]
- For the element in the first row, second column:
\[ 4 \times 3 = 12 \]
- For the element in the second row, first column:
\[ 4 \times (-1) = -4 \]
- For the element in the second row, second column:
\[ 4 \times 4 = 16 \]

3. **Construct the new matrix \( 4A \)**:
\[ 4A = \begin{pmatrix} 8 & 12 \\ -4 & 16 \end{pmatrix} \]

### Final Answer:
\[ 4A = \begin{pmatrix} 8 & 12 \\ -4 & 16 \end{pmatrix} \]