Quadratic Equation Solutions Explained

Jan 25, 2025

Solving Quadratic Equations Using the Quadratic Formula

Introduction

  • The goal is to solve quadratic equations of the form ( ax^2 + bx + c = 0 ) using the quadratic formula.
  • Quadratic formula: [ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} ]

Example 1: Solving ( 2x^2 + 3x - 2 = 0 )

  • Identify coefficients:
    • ( a = 2 )
    • ( b = 3 )
    • ( c = -2 )
  • Substitute into the quadratic formula:
    • ( x = \frac{-3 \pm \sqrt{3^2 - 4 \cdot 2 \cdot (-2)}}{2 \cdot 2} )
    • Calculation steps:
      • ( 3^2 = 9 )
      • ( -4 \cdot 2 \cdot (-2) = 16 )
      • ( 9 + 16 = 25 )
      • ( \sqrt{25} = 5 )
    • Resulting expressions:
      • ( x = \frac{-3 + 5}{4} ) and ( x = \frac{-3 - 5}{4} )
  • Simplify solutions:
    • ( x = \frac{2}{4} = \frac{1}{2} )
    • ( x = \frac{-8}{4} = -2 )
  • Solutions: ( x = \frac{1}{2} ) and ( x = -2 )
  • Verification:
    • Plug ( x = -2 ) back into the equation:
      • ( 2(-2)^2 + 3(-2) - 2 = 0 ) verifies the solution.

Example 2: Solving ( 6x^2 - 17x + 12 = 0 )

  • Identify coefficients:
    • ( a = 6 )
    • ( b = -17 )
    • ( c = 12 )
  • Substitute into the quadratic formula:
    • ( x = \frac{-(-17) \pm \sqrt{(-17)^2 - 4 \cdot 6 \cdot 12}}{2 \cdot 6} )
    • Calculation steps:
      • ( (-17)^2 = 289 )
      • ( -4 \cdot 6 \cdot 12 = -288 )
      • ( 289 - 288 = 1 )
      • ( \sqrt{1} = 1 )
    • Resulting expressions:
      • ( x = \frac{17 + 1}{12} ) and ( x = \frac{17 - 1}{12} )
  • Simplify solutions:
    • ( x = \frac{18}{12} = \frac{3}{2} )
    • ( x = \frac{16}{12} = \frac{4}{3} )
  • Solutions: ( x = \frac{3}{2} ) and ( x = \frac{4}{3} )

Conclusion

  • Successfully solved quadratic equations using the quadratic formula.
  • Verification of solutions ensures correctness.
  • Practice with different sets of quadratic equations to reinforce understanding.