Math Problem Statement

How do you solve quadratic equations?

Solution

To solve quadratic equations, you can use several methods. The most common ones are:

  1. Factoring
  2. Completing the Square
  3. Using the Quadratic Formula
  4. Graphing

1. Factoring

This method works when the quadratic equation can be factored into the product of two binomials. For example, solving x25x+6=0x^2 - 5x + 6 = 0:

x25x+6=(x2)(x3)=0x^2 - 5x + 6 = (x - 2)(x - 3) = 0

Set each factor to zero and solve for xx:

x2=0x=2x - 2 = 0 \quad \Rightarrow \quad x = 2 x3=0x=3x - 3 = 0 \quad \Rightarrow \quad x = 3

So, the solutions are x=2x = 2 and x=3x = 3.

2. Completing the Square

This method involves rewriting the quadratic equation in the form (xp)2=q(x - p)^2 = q. For example, solving x24x5=0x^2 - 4x - 5 = 0:

x24x=5x^2 - 4x = 5

Add 4 to both sides to complete the square:

x24x+4=9x^2 - 4x + 4 = 9

Rewrite the left side as a square:

(x2)2=9(x - 2)^2 = 9

Take the square root of both sides:

x2=±3x - 2 = \pm 3

Solve for xx:

x=2±3x = 2 \pm 3

So, the solutions are x=5x = 5 and x=1x = -1.

3. Using the Quadratic Formula

The quadratic formula can solve any quadratic equation of the form ax2+bx+c=0ax^2 + bx + c = 0:

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

For example, solving 2x24x6=02x^2 - 4x - 6 = 0:

a=2,b=4,c=6a = 2, \quad b = -4, \quad c = -6

Plug these values into the formula:

x=(4)±(4)242(6)22x = \frac{-(-4) \pm \sqrt{(-4)^2 - 4 \cdot 2 \cdot (-6)}}{2 \cdot 2}

Simplify inside the square root and solve:

x=4±16+484=4±644=4±84x = \frac{4 \pm \sqrt{16 + 48}}{4} = \frac{4 \pm \sqrt{64}}{4} = \frac{4 \pm 8}{4}

So, the solutions are:

x=4+84=3andx=484=1x = \frac{4 + 8}{4} = 3 \quad \text{and} \quad x = \frac{4 - 8}{4} = -1

4. Graphing

You can graph the quadratic equation and find the points where it intersects the x-axis. These points are the solutions.

Would you like any more details or have any other questions? Here are some related questions you might find interesting:

  1. Can you explain how to factor quadratic equations in more detail?
  2. How do you graph quadratic functions?
  3. What are the applications of the quadratic formula?
  4. How do you use the discriminant to determine the nature of the roots?
  5. Can you provide more examples of completing the square?

Tip: Always check if a quadratic equation can be factored first; it can often save time compared to other methods.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Factoring
Completing the Square
Quadratic Formula
Graphing

Formulas

Quadratic Formula

Theorems

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Suitable Grade Level

High School