Math Problem Statement

Solve for the following equations using the quadratic formula. Show your complete solution.

  1. x² + 7x + 12 = 0
  2. 2x² + 3x - 2 = 0
  3. x² - 6x + 9 = 0

Solution

To solve each of these quadratic equations using the quadratic formula, we follow the formula:

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

where aa, bb, and cc are the coefficients from the quadratic equation ax2+bx+c=0ax^2 + bx + c = 0.

1. Solve x2+7x+12=0x^2 + 7x + 12 = 0

  • Step 1: Identify the coefficients:

    • a=1a = 1, b=7b = 7, c=12c = 12
  • Step 2: Apply the quadratic formula: x=7±724(1)(12)2(1)x = \frac{-7 \pm \sqrt{7^2 - 4(1)(12)}}{2(1)} x=7±49482x = \frac{-7 \pm \sqrt{49 - 48}}{2} x=7±12x = \frac{-7 \pm \sqrt{1}}{2} x=7±12x = \frac{-7 \pm 1}{2}

  • Step 3: Solve for both possible values of xx:

    • x1=7+12=62=3x_1 = \frac{-7 + 1}{2} = \frac{-6}{2} = -3
    • x2=712=82=4x_2 = \frac{-7 - 1}{2} = \frac{-8}{2} = -4
  • Solution: x=3orx=4x = -3 \quad \text{or} \quad x = -4


2. Solve 2x2+3x2=02x^2 + 3x - 2 = 0

  • Step 1: Identify the coefficients:

    • a=2a = 2, b=3b = 3, c=2c = -2
  • Step 2: Apply the quadratic formula: x=3±324(2)(2)2(2)x = \frac{-3 \pm \sqrt{3^2 - 4(2)(-2)}}{2(2)} x=3±9+164x = \frac{-3 \pm \sqrt{9 + 16}}{4} x=3±254x = \frac{-3 \pm \sqrt{25}}{4} x=3±54x = \frac{-3 \pm 5}{4}

  • Step 3: Solve for both possible values of xx:

    • x1=3+54=24=12x_1 = \frac{-3 + 5}{4} = \frac{2}{4} = \frac{1}{2}
    • x2=354=84=2x_2 = \frac{-3 - 5}{4} = \frac{-8}{4} = -2
  • Solution: x=12orx=2x = \frac{1}{2} \quad \text{or} \quad x = -2


3. Solve x26x+9=0x^2 - 6x + 9 = 0

  • Step 1: Identify the coefficients:

    • a=1a = 1, b=6b = -6, c=9c = 9
  • Step 2: Apply the quadratic formula: x=(6)±(6)24(1)(9)2(1)x = \frac{-(-6) \pm \sqrt{(-6)^2 - 4(1)(9)}}{2(1)} x=6±36362x = \frac{6 \pm \sqrt{36 - 36}}{2} x=6±02x = \frac{6 \pm \sqrt{0}}{2} x=6±02x = \frac{6 \pm 0}{2}

  • Step 3: Solve for the single value of xx: x=62=3x = \frac{6}{2} = 3

  • Solution: x=3(a repeated root)x = 3 \quad (\text{a repeated root})


Summary of Solutions:

  1. x=3x = -3 or x=4x = -4
  2. x=12x = \frac{1}{2} or x=2x = -2
  3. x=3x = 3 (double root)

Would you like further clarification or details on any of the steps?

Here are 5 related questions for you:

  1. How do we determine when a quadratic has real, repeated, or complex roots?
  2. Can the quadratic formula be used for any type of quadratic equation?
  3. How does the discriminant in the quadratic formula affect the number of solutions?
  4. What happens when the value of b24acb^2 - 4ac is negative?
  5. Can you derive the quadratic formula from the process of completing the square?

Tip: The discriminant b24acb^2 - 4ac helps to quickly determine the nature of the roots: positive (real and distinct), zero (real and repeated), or negative (complex).

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Roots of Equations

Formulas

Quadratic Formula: x = (-b ± √(b² - 4ac)) / 2a

Theorems

Quadratic Formula
Discriminant Analysis

Suitable Grade Level

Grades 9-10