Math Problem Statement

If both the zeroes of a quadratic polynomials ax 2 + bx + c = 0 are equal and opposite is sign, find the value of b.

Solution

In a quadratic equation of the form ax2+bx+c=0ax^2 + bx + c = 0, the sum and product of the roots can be related to the coefficients using Vieta's formulas:

  • Sum of the roots: α+β=ba\alpha + \beta = -\frac{b}{a}
  • Product of the roots: αβ=ca\alpha \beta = \frac{c}{a}

Given that the two roots are equal and opposite in sign, we can denote the roots as α=r\alpha = r and β=r\beta = -r.

Step 1: Sum of the roots

The sum of the roots is: α+β=r+(r)=0\alpha + \beta = r + (-r) = 0

From Vieta's formula, we know: α+β=ba\alpha + \beta = -\frac{b}{a} So, we set: 0=ba0 = -\frac{b}{a} This implies: b=0b = 0

Conclusion:

The value of bb is 00.

Let me know if you'd like further clarification or if you have any other questions!


Related Questions:

  1. How does Vieta's formula work in general for any quadratic equation?
  2. What happens if the roots of a quadratic equation are real but not equal?
  3. Can we derive the quadratic equation if the sum and product of the roots are given?
  4. What is the discriminant, and how does it relate to the nature of the roots?
  5. What is the significance of the coefficients in determining the nature of the roots of a quadratic equation?

Tip: When the roots of a quadratic equation are equal and opposite, it indicates symmetry around the y-axis, making the equation symmetrical in its graph as well.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Vieta's Formulas

Formulas

Sum of the roots: α + β = -b/a
Product of the roots: αβ = c/a

Theorems

Vieta's Formulas

Suitable Grade Level

Grades 9-11