Math Problem Statement

solve this math (as shown in pic) with completing square method.

Solution

The given equation in the image is:

(2x1)2(2x+1)24x21=43\frac{(2x - 1)^2 - (2x + 1)^2}{4x^2 - 1} = -\frac{4}{3}

Let's solve this step by step using the completing square method.

Step 1: Expand the squared terms

We have two squared terms in the numerator: (2x1)2and(2x+1)2(2x - 1)^2 \quad \text{and} \quad (2x + 1)^2

Expanding each of them:

(2x1)2=4x24x+1(2x - 1)^2 = 4x^2 - 4x + 1

(2x+1)2=4x2+4x+1(2x + 1)^2 = 4x^2 + 4x + 1

Step 2: Substitute the expanded forms back into the equation

Substituting the expanded forms:

(4x24x+1)(4x2+4x+1)4x21=43\frac{(4x^2 - 4x + 1) - (4x^2 + 4x + 1)}{4x^2 - 1} = -\frac{4}{3}

Step 3: Simplify the numerator

Simplifying the numerator:

(4x24x+1)(4x2+4x+1)=4x24x+14x24x1(4x^2 - 4x + 1) - (4x^2 + 4x + 1) = 4x^2 - 4x + 1 - 4x^2 - 4x - 1

=8x= -8x

Now the equation becomes:

8x4x21=43\frac{-8x}{4x^2 - 1} = -\frac{4}{3}

Step 4: Cross-multiply to simplify

Cross-multiply to get rid of the fraction:

8x3=4(4x21)-8x \cdot 3 = -4 \cdot (4x^2 - 1)

Simplifying:

24x=16x2+4-24x = -16x^2 + 4

Step 5: Rearrange the equation

Rearrange all terms to one side to set the equation to zero:

16x224x+4=016x^2 - 24x + 4 = 0

Step 6: Factor or use the quadratic formula

The equation is now a quadratic equation:

16x224x+4=016x^2 - 24x + 4 = 0

To solve by completing the square:

  1. Divide the equation by 16: x232x+14=0x^2 - \frac{3}{2}x + \frac{1}{4} = 0

  2. Move the constant term to the right side: x232x=14x^2 - \frac{3}{2}x = -\frac{1}{4}

  3. Complete the square by adding and subtracting (34)2\left(\frac{3}{4}\right)^2 on the left side: x232x+916=91614x^2 - \frac{3}{2}x + \frac{9}{16} = \frac{9}{16} - \frac{1}{4}

  4. Simplify the right side: (x34)2=516\left(x - \frac{3}{4}\right)^2 = \frac{5}{16}

  5. Take the square root of both sides: x34=±54x - \frac{3}{4} = \pm \frac{\sqrt{5}}{4}

  6. Solve for xx: x=3±54x = \frac{3 \pm \sqrt{5}}{4}

Thus, the solutions are:

x=3+54andx=354x = \frac{3 + \sqrt{5}}{4} \quad \text{and} \quad x = \frac{3 - \sqrt{5}}{4}

Would you like further details on this solution or have any other questions?

Follow-Up Questions

  1. What is the next step after finding the roots of a quadratic equation?
  2. How does completing the square help in solving quadratic equations?
  3. Can this problem be solved using a different method, such as the quadratic formula?
  4. What does the discriminant tell us about the nature of the roots in a quadratic equation?
  5. How would the problem change if the original equation was set equal to a different constant?

Tip

When solving quadratic equations, always check if factoring is possible before moving on to other methods like completing the square or the quadratic formula.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Completing the Square
Solving Equations
Algebra

Formulas

Quadratic equation formula
Completing the square method

Theorems

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Suitable Grade Level

Grades 10-12