• A quadratic equation is a polynomial equation of degree 2. It can be expressed in the general form:
    ax² + bx + c = 0
    
    where a, b, and c are constants, and a ≠ 0.

Methods for Solving Quadratic Equations:

  1. Factoring:

    • Factor the quadratic expression into two linear factors.
    • Set each factor equal to zero and solve for x.
    • Example:
      x² - 5x + 6 = 0
      (x - 2)(x - 3) = 0
      x = 2 or x = 3
      
  2. Completing the Square:

    • Convert the quadratic equation into a perfect square trinomial.
    • Take the square root of both sides and solve for x.
    • Example:
      x² - 6x + 2 = 0
      x² - 6x + 9 = 7
      (x - 3)² = 7
      x - 3 = ±√7
      x = 3 ± √7
      
  3. Quadratic Formula:

    • Apply the quadratic formula:
      x = (-b ± √(b² - 4ac)) / (2a)
      
    • Substitute the values of a, b, and c from the quadratic equation.
    • Simplify and solve for x.

Example:

Solve the equation: 2x² - 3x - 5 = 0

Method 1: Factoring

  • We cannot factor this equation into two linear factors.

Method 2: Completing the Square

  • Divide the equation by 2 to simplify:
    x² - (3/2)x - (5/2) = 0
    
  • Add (3/4)² to both sides to complete the square:
    x² - (3/2)x + (9/16) = (9/16) + (5/2)
    (x - 3/4)² = 49/16
    x - 3/4 = ±7/4
    x = 3/4 ± 7/4
    x = 5/2 or x = -1
    

Method 3: Quadratic Formula

  • Substitute a = 2, b = -3, and c = -5 into the formula:
    x = (-(-3) ± √((-3)² - 4(2)(-5))) / (2(2))
    x = (3 ± √49) / 4
    x = (3 ± 7) / 4
    x = 5/2 or x = -1
    

Choosing the Best Method:

  • Factoring is often the quickest method if it's possible.
  • Completing the square is useful when the quadratic equation is not easily factored.
  • The quadratic formula is always applicable, even if factoring or completing the square is difficult.

I hope this explanation helps! Feel free to ask if you have any more questions.