Solve Quadratics - When the Independent Term is Zero

Algebra-1

1. Fundamental Concepts

  • Definition: The general form of a quadratic equation is  (). When the independent term (constant term) , the equation simplifies to .
  • Core Feature: The equation contains no constant term, and all terms include the variable x. Thus, it can be solved by factoring out the common factor.

2. Key Concepts

  • Simplified Equation Form ().
  • Solution Principle: By factoring out the common factor x, the equation is transformed into . Using the property that "if the product of two factors is 0, at least one of the factors must be 0," we get:
    •  or 
    • Solving these gives two roots:  and .
  • Characteristic of Roots: One root is always , and the other root is determined by the coefficients of the linear term and the quadratic term.

3. Examples

  • Easy: Solve the equation 
  • Solution: Factor out the common factor x, resulting in  .Then  or , so  and .
  • Medium: Solve the equation 
  • Solution: Factor out the common factor 3x, resulting in  .Then  or , so  and .
  • Hard: Solve the equation 
  • Solution: Factor out the common factor , resulting in  .Then  or , so  and .

4. Problem-Solving Techniques

  • Identify the Equation Type: Confirm that the constant term  in the quadratic equation, i.e., the equation is in the form .
  • Factor Out the Common Factor: Extract the common factor containing x to transform the equation into the product form .
  • Solve for Each Factor: Set each factor equal to 0 separately and solve for the two roots (one of which is always 0).
  • Verify the Results (optional): Substitute the solutions back into the original equation to check if they satisfy the equality (to ensure correctness).