Math Problem Statement

Solve 2x^2 - 7x + 3 = 0 by completing the square.

Solution

To solve the quadratic equation 2x27x+3=02x^2 - 7x + 3 = 0 by completing the square, let's go through the following steps:

Step 1: Divide by the Leading Coefficient

First, divide the entire equation by 2 to make the coefficient of x2x^2 equal to 1.

2x27x+3=0    x272x+32=02x^2 - 7x + 3 = 0 \implies x^2 - \frac{7}{2}x + \frac{3}{2} = 0

Step 2: Move the Constant Term to the Right Side

x272x=32x^2 - \frac{7}{2}x = -\frac{3}{2}

Step 3: Complete the Square

To complete the square, take half of the coefficient of xx, square it, and add it to both sides. The coefficient of xx is 72-\frac{7}{2}. Half of this is 74-\frac{7}{4}, and squaring it gives (74)2=4916\left(-\frac{7}{4}\right)^2 = \frac{49}{16}.

Add 4916\frac{49}{16} to both sides:

x272x+4916=32+4916x^2 - \frac{7}{2}x + \frac{49}{16} = -\frac{3}{2} + \frac{49}{16}

Step 4: Simplify the Right Side

Convert 32-\frac{3}{2} to a fraction with a denominator of 16:

32=2416-\frac{3}{2} = -\frac{24}{16}

So:

2416+4916=2516-\frac{24}{16} + \frac{49}{16} = \frac{25}{16}

Now, the equation looks like:

(x74)2=2516\left(x - \frac{7}{4}\right)^2 = \frac{25}{16}

Step 5: Take the Square Root of Both Sides

x74=±54x - \frac{7}{4} = \pm \frac{5}{4}

This gives us two equations:

  1. x74=54x - \frac{7}{4} = \frac{5}{4}
  2. x74=54x - \frac{7}{4} = -\frac{5}{4}

Step 6: Solve for xx

  1. For x74=54x - \frac{7}{4} = \frac{5}{4}:

x=74+54=124=3x = \frac{7}{4} + \frac{5}{4} = \frac{12}{4} = 3

  1. For x74=54x - \frac{7}{4} = -\frac{5}{4}:

x=7454=24=12x = \frac{7}{4} - \frac{5}{4} = \frac{2}{4} = \frac{1}{2}

Solution

The solutions are x=3x = 3 and x=12x = \frac{1}{2}. The correct answer is:

x=3,12\boxed{x = 3, \frac{1}{2}}

This matches the fourth option in the problem.

Do you have any questions or would you like more details on any part of the solution?

Here are 5 related questions to expand your understanding:

  1. How do you solve a quadratic equation using the quadratic formula?
  2. Why is it necessary to complete the square when solving quadratics?
  3. How would the process change if the equation had no real roots?
  4. What are some real-world applications of solving quadratic equations?
  5. Can you complete the square when the quadratic term coefficient is not easily divisible?

Tip: When completing the square, always ensure the coefficient of x2x^2 is 1 by dividing through, if necessary.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Completing the Square

Formulas

Standard quadratic form: ax^2 + bx + c = 0
Formula for completing the square: (b/2)^2

Theorems

Method of completing the square

Suitable Grade Level

Grades 9-11