Find 4A + 3B. 7 1 A = 4 2 4A + 3B = B = - 3 3 2 -6

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ChapterP: Prerequisites: Fundamental Concepts Of Algebra
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Problem 1MCCP: In Exercises 1-25, simplify the given expression or perform the indicated operation (and simplify,...
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### Matrix Addition and Scalar Multiplication

**Problem:**
Find \( 4A + 3B \).

Given matrices:
\[ A = \begin{bmatrix} 7 & 1 \\ 4 & 2 \end{bmatrix} \]
\[ B = \begin{bmatrix} -3 & 2 \\ 3 & -6 \end{bmatrix} \]

### Solution:

1. **Scalar Multiplication:**

   First, multiply matrix \( A \) by 4:
   \[
   4A = 4 \times \begin{bmatrix} 7 & 1 \\ 4 & 2 \end{bmatrix} = \begin{bmatrix} 4 \times 7 & 4 \times 1 \\ 4 \times 4 & 4 \times 2 \end{bmatrix} = \begin{bmatrix} 28 & 4 \\ 16 & 8 \end{bmatrix}
   \]

   Then, multiply matrix \( B \) by 3:
   \[
   3B = 3 \times \begin{bmatrix} -3 & 2 \\ 3 & -6 \end{bmatrix} = \begin{bmatrix} 3 \times -3 & 3 \times 2 \\ 3 \times 3 & 3 \times -6 \end{bmatrix} = \begin{bmatrix} -9 & 6 \\ 9 & -18 \end{bmatrix}
   \]

2. **Matrix Addition:**

   Now add the results from the above scalar multiplications:
   \[
   4A + 3B = \begin{bmatrix} 28 & 4 \\ 16 & 8 \end{bmatrix} + \begin{bmatrix} -9 & 6 \\ 9 & -18 \end{bmatrix} = \begin{bmatrix} 28 + (-9) & 4 + 6 \\ 16 + 9 & 8 + (-18) \end{bmatrix} = \begin{bmatrix} 19 & 10 \\ 25 & -10 \end{bmatrix}
   \]

Therefore, 
\[ 4A + 3B = \begin{bmatrix} 19 & 10 \\ 25 & -10 \end{bmatrix
Transcribed Image Text:### Matrix Addition and Scalar Multiplication **Problem:** Find \( 4A + 3B \). Given matrices: \[ A = \begin{bmatrix} 7 & 1 \\ 4 & 2 \end{bmatrix} \] \[ B = \begin{bmatrix} -3 & 2 \\ 3 & -6 \end{bmatrix} \] ### Solution: 1. **Scalar Multiplication:** First, multiply matrix \( A \) by 4: \[ 4A = 4 \times \begin{bmatrix} 7 & 1 \\ 4 & 2 \end{bmatrix} = \begin{bmatrix} 4 \times 7 & 4 \times 1 \\ 4 \times 4 & 4 \times 2 \end{bmatrix} = \begin{bmatrix} 28 & 4 \\ 16 & 8 \end{bmatrix} \] Then, multiply matrix \( B \) by 3: \[ 3B = 3 \times \begin{bmatrix} -3 & 2 \\ 3 & -6 \end{bmatrix} = \begin{bmatrix} 3 \times -3 & 3 \times 2 \\ 3 \times 3 & 3 \times -6 \end{bmatrix} = \begin{bmatrix} -9 & 6 \\ 9 & -18 \end{bmatrix} \] 2. **Matrix Addition:** Now add the results from the above scalar multiplications: \[ 4A + 3B = \begin{bmatrix} 28 & 4 \\ 16 & 8 \end{bmatrix} + \begin{bmatrix} -9 & 6 \\ 9 & -18 \end{bmatrix} = \begin{bmatrix} 28 + (-9) & 4 + 6 \\ 16 + 9 & 8 + (-18) \end{bmatrix} = \begin{bmatrix} 19 & 10 \\ 25 & -10 \end{bmatrix} \] Therefore, \[ 4A + 3B = \begin{bmatrix} 19 & 10 \\ 25 & -10 \end{bmatrix
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