Math Problem Statement

If A = [[1, 6], [-7, 5]], B = [[6], [-7]], C = [[8], [-11]], then find X when X = A^2 - 2BC.

Solution

The problem in the image involves matrix operations. The given matrices are:

A=[1675],B=[67],C=[811]A = \begin{bmatrix} 1 & 6 \\ -7 & 5 \end{bmatrix}, \quad B = \begin{bmatrix} 6 \\ -7 \end{bmatrix}, \quad C = \begin{bmatrix} 8 \\ -11 \end{bmatrix}

You are asked to find XX where X=A22BCX = A^2 - 2BC.

Step 1: Calculate A2A^2

First, we need to calculate A2A^2, which is A×AA \times A.

A2=[1675]×[1675]A^2 = \begin{bmatrix} 1 & 6 \\ -7 & 5 \end{bmatrix} \times \begin{bmatrix} 1 & 6 \\ -7 & 5 \end{bmatrix}

Multiply the matrices:

(1 \times 1 + 6 \times -7) & (1 \times 6 + 6 \times 5) \\ (-7 \times 1 + 5 \times -7) & (-7 \times 6 + 5 \times 5) \end{bmatrix}$$ $$A^2 = \begin{bmatrix} 1 - 42 & 6 + 30 \\ -7 - 35 & -42 + 25 \end{bmatrix}$$ $$A^2 = \begin{bmatrix} -41 & 36 \\ -42 & -17 \end{bmatrix}$$ ### Step 2: Calculate $$2BC$$ Next, calculate $$2BC$$: $$2BC = 2 \times \left(\begin{bmatrix} 6 \\ -7 \end{bmatrix} \times \begin{bmatrix} 8 & -11 \end{bmatrix}\right)$$ The multiplication of $$B$$ and $$C$$ gives: $$BC = \begin{bmatrix} 6 \times 8 & 6 \times -11 \\ -7 \times 8 & -7 \times -11 \end{bmatrix} = \begin{bmatrix} 48 & -66 \\ -56 & 77 \end{bmatrix}$$ Now multiply by 2: $$2BC = \begin{bmatrix} 96 & -132 \\ -112 & 154 \end{bmatrix}$$ ### Step 3: Calculate $$X = A^2 - 2BC$$ $$X = \begin{bmatrix} -41 & 36 \\ -42 & -17 \end{bmatrix} - \begin{bmatrix} 96 & -132 \\ -112 & 154 \end{bmatrix}$$ Subtract the matrices: $$X = \begin{bmatrix} -41 - 96 & 36 + 132 \\ -42 + 112 & -17 - 154 \end{bmatrix}$$ $$X = \begin{bmatrix} -137 & 168 \\ 70 & -171 \end{bmatrix}$$ ### Final Answer $$X = \begin{bmatrix} -137 & 168 \\ 70 & -171 \end{bmatrix}$$ Would you like any further details or clarifications on this problem? Here are five related questions you might be interested in: 1. How do you perform matrix multiplication for larger matrices? 2. What is the significance of the determinant in matrix operations? 3. Can matrices with different dimensions be multiplied? 4. How do you find the inverse of a matrix? 5. What are some real-world applications of matrix operations? **Tip:** When performing matrix operations, always double-check the dimensions to ensure that the multiplication is valid.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Matrix Multiplication
Matrix Subtraction
Algebra

Formulas

Matrix Multiplication: (AB)_{ij} = \sum_{k=1}^{n} A_{ik}B_{kj}
Matrix Subtraction: (A - B)_{ij} = A_{ij} - B_{ij}

Theorems

Properties of Matrices

Suitable Grade Level

Undergraduate Level or Advanced High School