Math Problem Statement

Examine the graph of the quadratic function y = x^2 - 2x - 3 and answer several questions about the graph.

Solution

Let's analyze the problem given in the image. The task revolves around a quadratic function y=x22x3y = x^2 - 2x - 3 and involves answering several questions based on its graph.

The questions are:

a. How would you describe the graph?

This is a parabola, opening upwards. The shape is symmetric around the vertical axis passing through the vertex.

b. Give the vertex of the parabola and its axis of symmetry.

The vertex of a parabola given by y=ax2+bx+cy = ax^2 + bx + c can be found using the formula for the x-coordinate of the vertex: x=b2ax = \frac{-b}{2a} Here, a=1a = 1, b=2b = -2, and c=3c = -3. So: x=(2)2(1)=1x = \frac{-(-2)}{2(1)} = 1 Substitute x=1x = 1 into the equation to find the y-coordinate of the vertex: y=122(1)3=123=4y = 1^2 - 2(1) - 3 = 1 - 2 - 3 = -4 Thus, the vertex is (1,4)(1, -4), and the axis of symmetry is the vertical line x=1x = 1.

c. At what values of xx does the graph intersect the x-axis?

The x-intercepts can be found by solving x22x3=0x^2 - 2x - 3 = 0. Factoring the quadratic: (x3)(x+1)=0(x - 3)(x + 1) = 0 Thus, the x-intercepts are x=3x = 3 and x=1x = -1.

d. What do you call these x-coordinates where the curve crosses the x-axis?

These x-coordinates are called the zeros or roots of the quadratic function.

e. What is the value of yy at these values of xx?

At the x-intercepts, y=0y = 0, since the graph crosses the x-axis at those points.


Would you like further details on any of these points?

Here are five related questions for further understanding:

  1. What is the significance of the vertex in a quadratic graph?
  2. How does the coefficient of x2x^2 (positive or negative) affect the direction of the parabola?
  3. How do you determine if a quadratic function has two, one, or no x-intercepts?
  4. Can the axis of symmetry ever be horizontal? Why or why not?
  5. What other methods can be used to find the zeros of a quadratic function?

Tip: Remember, the discriminant Δ=b24ac\Delta = b^2 - 4ac of the quadratic equation tells you how many real roots (zeros) the function has.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Parabolas
Zeros of Functions
Vertex
Axis of Symmetry

Formulas

Vertex formula: x = -b/(2a)
Quadratic equation: ax^2 + bx + c = 0
Factoring: (x - 3)(x + 1) = 0

Theorems

Quadratic function properties
Factoring to find zeros
Axis of symmetry of parabolas

Suitable Grade Level

Grades 8-10