Math Problem Statement

Solve the matrix equation: X * ( 3 -4 -5 6 ) = ( 5 1 2 0 )

Solution

The given problem is a matrix equation that needs to be solved. The equation is written as:

X(3456)=(5120)X \cdot \begin{pmatrix} 3 & -4 \\ -5 & 6 \end{pmatrix} = \begin{pmatrix} 5 & 1 \\ 2 & 0 \end{pmatrix}

To solve for XX, we need to multiply both sides of the equation by the inverse of the matrix on the left. The steps are as follows:

1. Find the inverse of matrix A=(3456)A = \begin{pmatrix} 3 & -4 \\ -5 & 6 \end{pmatrix}.

The inverse of a 2x2 matrix A=(abcd)A = \begin{pmatrix} a & b \\ c & d \end{pmatrix} is given by:

A1=1adbc(dbca)A^{-1} = \frac{1}{ad - bc} \begin{pmatrix} d & -b \\ -c & a \end{pmatrix}

In this case, a=3a = 3, b=4b = -4, c=5c = -5, and d=6d = 6.

The determinant is:

det(A)=(3)(6)(4)(5)=1820=2\text{det}(A) = (3)(6) - (-4)(-5) = 18 - 20 = -2

Thus, the inverse of AA is:

A1=12(6453)=(325232)A^{-1} = \frac{1}{-2} \begin{pmatrix} 6 & 4 \\ 5 & 3 \end{pmatrix} = \begin{pmatrix} -3 & -2 \\ -\frac{5}{2} & -\frac{3}{2} \end{pmatrix}

2. Multiply both sides of the equation by A1A^{-1} on the left:

X=(5120)A1X = \begin{pmatrix} 5 & 1 \\ 2 & 0 \end{pmatrix} \cdot A^{-1}

Now, perform the matrix multiplication:

X=(5120)(325232)X = \begin{pmatrix} 5 & 1 \\ 2 & 0 \end{pmatrix} \cdot \begin{pmatrix} -3 & -2 \\ -\frac{5}{2} & -\frac{3}{2} \end{pmatrix}

3. Multiply the matrices:

X=((5)(3)+(1)(52)(5)(2)+(1)(32)(2)(3)+(0)(52)(2)(2)+(0)(32))X = \begin{pmatrix} (5)(-3) + (1)\left(-\frac{5}{2}\right) & (5)(-2) + (1)\left(-\frac{3}{2}\right) \\ (2)(-3) + (0)\left(-\frac{5}{2}\right) & (2)(-2) + (0)\left(-\frac{3}{2}\right) \end{pmatrix}

Simplifying:

= \begin{pmatrix} -\frac{35}{2} & -\frac{23}{2} \\ -6 & -4 \end{pmatrix}$$ Thus, the solution is: $$X = \begin{pmatrix} -\frac{35}{2} & -\frac{23}{2} \\ -6 & -4 \end{pmatrix}$$ --- Would you like more details or have any questions on this? Here are 5 related questions to consider: 1. How do you find the determinant of a matrix? 2. What are the conditions for a matrix to have an inverse? 3. How do you multiply two matrices together? 4. What is the significance of the determinant being zero? 5. How can matrix equations be used in solving systems of linear equations? **Tip:** Always check that the determinant of a matrix is non-zero before attempting to find its inverse!

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Matrix Equations
Matrix Inverses

Formulas

Matrix inverse formula for 2x2 matrix: A⁻¹ = (1/(ad - bc)) * [d -b -c a]
Matrix multiplication formula

Theorems

Determinant and Inverse Theorem

Suitable Grade Level

College-level or advanced high school math