Math Problem Statement

Solve the quadratic equation x^2 - 3x - 5 = 0 by completing the square.

Solution

The problem requires solving the quadratic equation x23x5=0x^2 - 3x - 5 = 0 using the completing the square method. Let’s solve it step by step:


Step 1: Rearrange the equation

Bring the constant term (5-5) to the other side: x23x=5x^2 - 3x = 5


Step 2: Complete the square

Take half the coefficient of xx (which is 3-3), square it, and add it to both sides: (32)2=94\left(\frac{-3}{2}\right)^2 = \frac{9}{4} Add 94\frac{9}{4} to both sides: x23x+94=5+94x^2 - 3x + \frac{9}{4} = 5 + \frac{9}{4}


Step 3: Simplify both sides

The left-hand side becomes a perfect square trinomial: (x32)2=204+94=294\left(x - \frac{3}{2}\right)^2 = \frac{20}{4} + \frac{9}{4} = \frac{29}{4}


Step 4: Solve for xx

Take the square root of both sides: x32=±294x - \frac{3}{2} = \pm \sqrt{\frac{29}{4}} Simplify the square root: x32=±292x - \frac{3}{2} = \pm \frac{\sqrt{29}}{2}


Step 5: Isolate xx

Add 32\frac{3}{2} to both sides: x=32±292x = \frac{3}{2} \pm \frac{\sqrt{29}}{2}

Combine the terms into a single fraction: x=3±292x = \frac{3 \pm \sqrt{29}}{2}


Final Answer:

The solutions are: x=3+292andx=3292.x = \frac{3 + \sqrt{29}}{2} \quad \text{and} \quad x = \frac{3 - \sqrt{29}}{2}.


Would you like further clarification, or do you have additional questions?

Here are some related questions for practice:

  1. How do you apply completing the square when the coefficient of x2x^2 is not 1?
  2. How does completing the square relate to the quadratic formula?
  3. What is the geometric meaning of completing the square?
  4. Can you derive the vertex form of a quadratic equation using this method?
  5. How does adding and subtracting terms affect equality in an equation?

Tip: Always ensure the coefficient of x2x^2 is 1 before starting the completing-the-square process.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Completing the Square

Formulas

(b/2)^2 to complete the square
Square root property to solve quadratic equations

Theorems

Equality property of equations
Properties of perfect square trinomials

Suitable Grade Level

Grades 9-11