Math Problem Statement

If the matrix (6 - 2x, x; x, 2) has no inverse, then x = ?

Solution

The image shows part of a mathematical problem. The text is as follows:

"If (62xxx2)\begin{pmatrix} 6 - 2x & x \\ x & 2 \end{pmatrix} has no inverse, then x=x ="

To solve this, we need to recall that a matrix has no inverse if its determinant is zero. The determinant of a 2x2 matrix (abcd)\begin{pmatrix} a & b \\ c & d \end{pmatrix} is calculated as:

det=adbc\text{det} = ad - bc

In this case, for the matrix:

(62xxx2)\begin{pmatrix} 6 - 2x & x \\ x & 2 \end{pmatrix}

The determinant is:

det=(62x)(2)(x)(x)=124xx2\text{det} = (6 - 2x)(2) - (x)(x) = 12 - 4x - x^2

For the matrix to have no inverse, the determinant must be equal to zero:

124xx2=012 - 4x - x^2 = 0

This simplifies to the quadratic equation:

x2+4x12=0x^2 + 4x - 12 = 0

Now we can solve this quadratic equation using the quadratic formula:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

where a=1a = 1, b=4b = 4, and c=12c = -12.

Let me calculate that for you.The solutions to the equation x2+4x12=0x^2 + 4x - 12 = 0 are:

x=2orx=6x = 2 \quad \text{or} \quad x = -6

Therefore, xx can be either 2 or -6 for the matrix to have no inverse.

Would you like more details or have any questions?

Here are 5 related questions:

  1. How is the determinant of a 2x2 matrix calculated in general?
  2. What does it mean for a matrix to have no inverse?
  3. Could we have used a different method to solve the quadratic equation?
  4. What are the properties of a matrix that has an inverse?
  5. How does the quadratic formula work, and when should it be applied?

Tip: Always check the discriminant when solving quadratic equations to determine if the solutions are real, complex, or if there's only one solution.

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Math Problem Analysis

Mathematical Concepts

Matrix Algebra
Determinants
Quadratic Equations

Formulas

Determinant of a 2x2 matrix: det = ad - bc
Quadratic equation: ax^2 + bx + c = 0
Quadratic formula: x = (-b ± sqrt(b^2 - 4ac)) / 2a

Theorems

Determinant condition for inverse matrices
Quadratic Formula

Suitable Grade Level

Grade 10-12