Math Problem Statement

Analyze the graph of the quadratic function y = ax^2 + bx + c and determine the correct statement about the coefficients.

Solution

The given image shows a quadratic function y=ax2+bx+cy = ax^2 + bx + c and a graph of the parabola. The options involve conditions on abab and a+b+ca + b + c. Let’s analyze the graph and the choices step-by-step:

Observations from the graph:

  1. The parabola opens upwards, which means a>0a > 0.
  2. The parabola crosses the x-axis twice, indicating that the quadratic equation has two real roots. Therefore, the discriminant (Δ=b24ac\Delta = b^2 - 4ac) must be positive.
  3. The product of the roots is ca\frac{c}{a}, and the sum of the roots is ba-\frac{b}{a}. While this might not be directly needed, it helps analyze the graph.

Considering the statements:

  • Sign of abab: Since a>0a > 0, the sign of abab depends on bb. From the graph, the parabola's axis is on the left of the origin (negative xx-coordinate), which indicates b>0b > 0. Thus, ab>0ab > 0.
  • Sign of a+b+ca + b + c: The y-intercept of the parabola is cc. Since the graph starts below the x-axis but eventually rises, cc and a+b+ca + b + c must be greater than 0.

Correct answer:

The correct statement is A: ab>0ab > 0 and a+b+c>0a + b + c > 0.


Would you like a detailed explanation of the conditions for each statement?

Here are 5 questions that expand on this topic:

  1. What is the role of the discriminant (Δ\Delta) in determining the number of roots for a quadratic equation?
  2. How does the sign of aa affect the direction of a parabola?
  3. Can a+b+ca + b + c provide insights into the behavior of a quadratic function for x=1x = 1?
  4. What happens to the product abab when b<0b < 0 and a>0a > 0?
  5. How can the vertex form of a quadratic equation (y=a(xh)2+ky = a(x-h)^2 + k) help analyze the parabola’s properties?

Tip:

For quadratic functions, always verify the sign of aa first, as it determines the overall shape of the graph (upwards or downwards).

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Graph Analysis
Inequalities

Formulas

General form of a quadratic equation: y = ax^2 + bx + c
Discriminant: Δ = b^2 - 4ac
Vertex form of a quadratic function: y = a(x-h)^2 + k

Theorems

Sign Analysis of Coefficients
Discriminant and Roots Relationship

Suitable Grade Level

Grades 10-12