Math Problem Statement

Three matrices are shown below. A = [4 1; -3 0], B = [-2 3; -5 1], C = [5 -1; 2 3]. Perform the matrix operations 3A, A + B, and BC, selecting the correct answers from the options provided.

Solution

Let's break down each matrix operation given and solve them individually.

  1. Matrix Definitions:

    • A=[4130]A = \begin{bmatrix} 4 & 1 \\ -3 & 0 \end{bmatrix}
    • B=[2351]B = \begin{bmatrix} -2 & 3 \\ -5 & 1 \end{bmatrix}
    • C=[5123]C = \begin{bmatrix} 5 & -1 \\ 2 & 3 \end{bmatrix}
  2. Calculating 3A3A: To find 3A3A, multiply each element of matrix AA by 3: 3A=3×[4130]=[12390]3A = 3 \times \begin{bmatrix} 4 & 1 \\ -3 & 0 \end{bmatrix} = \begin{bmatrix} 12 & 3 \\ -9 & 0 \end{bmatrix}

  3. Calculating A+BA + B: To add AA and BB, add the corresponding elements: A+B=[4130]+[2351]=[4+(2)1+33+(5)0+1]=[2481]A + B = \begin{bmatrix} 4 & 1 \\ -3 & 0 \end{bmatrix} + \begin{bmatrix} -2 & 3 \\ -5 & 1 \end{bmatrix} = \begin{bmatrix} 4 + (-2) & 1 + 3 \\ -3 + (-5) & 0 + 1 \end{bmatrix} = \begin{bmatrix} 2 & 4 \\ -8 & 1 \end{bmatrix}

  4. Calculating BCBC: To multiply matrices BB and CC, perform the matrix multiplication: BC=[2351]×[5123]BC = \begin{bmatrix} -2 & 3 \\ -5 & 1 \end{bmatrix} \times \begin{bmatrix} 5 & -1 \\ 2 & 3 \end{bmatrix} Calculating each element:

    • Top-left: (2×5)+(3×2)=10+6=4(-2 \times 5) + (3 \times 2) = -10 + 6 = -4
    • Top-right: (2×1)+(3×3)=2+9=11(-2 \times -1) + (3 \times 3) = 2 + 9 = 11
    • Bottom-left: (5×5)+(1×2)=25+2=23(-5 \times 5) + (1 \times 2) = -25 + 2 = -23
    • Bottom-right: (5×1)+(1×3)=5+3=8(-5 \times -1) + (1 \times 3) = 5 + 3 = 8

    So, BC=[411238]BC = \begin{bmatrix} -4 & 11 \\ -23 & 8 \end{bmatrix}

Summary of Results:

  • 3A=[12390]3A = \begin{bmatrix} 12 & 3 \\ -9 & 0 \end{bmatrix}
  • A+B=[2481]A + B = \begin{bmatrix} 2 & 4 \\ -8 & 1 \end{bmatrix}
  • BC=[411238]BC = \begin{bmatrix} -4 & 11 \\ -23 & 8 \end{bmatrix}

Now, you can match these results with the provided options in your answer choices.

Would you like further explanations on any part of this? Here are a few questions to expand on the concept:

  1. How is scalar multiplication of matrices performed?
  2. What are the conditions for matrix addition and subtraction?
  3. Can all matrices be multiplied with each other? If not, what are the conditions?
  4. What happens when you multiply a matrix by an identity matrix?
  5. How do these operations apply in real-world scenarios?

Tip: When multiplying matrices, remember that the number of columns in the first matrix must equal the number of rows in the second matrix for multiplication to be possible.

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Math Problem Analysis

Mathematical Concepts

Matrix Multiplication
Scalar Multiplication
Matrix Addition

Formulas

Scalar Multiplication: kA = k * A for each element of matrix A
Matrix Addition: A + B is element-wise addition of matrices A and B
Matrix Multiplication: AB is defined if the number of columns in A equals the number of rows in B

Theorems

Properties of Matrix Multiplication and Addition

Suitable Grade Level

Grades 10-12