Math Problem Statement

Sketch the graph of f(x) = x^2 - 4x +9. The sketch must include the coordinates of any points where the graph of f(x) = x^2 - 4x +9 meets the coordinate axes.

Solution

To sketch the graph of the quadratic function f(x)=x24x+9f(x) = x^2 - 4x + 9, follow these steps:

1. Find the Vertex:

The quadratic function is in the form f(x)=ax2+bx+cf(x) = ax^2 + bx + c. For this function: a=1,b=4,c=9a = 1, \quad b = -4, \quad c = 9 The x-coordinate of the vertex is given by: x=b2a=42(1)=42=2x = -\frac{b}{2a} = -\frac{-4}{2(1)} = \frac{4}{2} = 2 Substituting x=2x = 2 into the function to find the y-coordinate: f(2)=(2)24(2)+9=48+9=5f(2) = (2)^2 - 4(2) + 9 = 4 - 8 + 9 = 5 So, the vertex is at (2,5)(2, 5).

2. Determine the Y-intercept:

The y-intercept is found by evaluating the function at x=0x = 0: f(0)=(0)24(0)+9=9f(0) = (0)^2 - 4(0) + 9 = 9 So, the graph meets the y-axis at (0,9)(0, 9).

3. Determine the X-intercepts:

The x-intercepts are found by solving the equation f(x)=0f(x) = 0: x24x+9=0x^2 - 4x + 9 = 0 The discriminant (b24acb^2 - 4ac) for this quadratic is: (4)24(1)(9)=1636=20(-4)^2 - 4(1)(9) = 16 - 36 = -20 Since the discriminant is negative, the quadratic equation has no real solutions, meaning the graph does not intersect the x-axis.

4. Sketch the Graph:

  • The graph is a parabola opening upwards because a>0a > 0.
  • The vertex is at (2,5)(2, 5).
  • The graph crosses the y-axis at (0,9)(0, 9).
  • There are no x-intercepts.

Graphical Sketch:

  • The parabola opens upwards with its vertex at (2,5)(2, 5).
  • The y-intercept is at (0,9)(0, 9).
  • The parabola is symmetric about the vertical line x=2x = 2.

If you would like me to generate an actual visual representation of this sketch, I can do that too. Would you like to see the graph?

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Graphing Parabolas

Formulas

Vertex formula: x = -b / (2a)
Discriminant formula: b^2 - 4ac

Theorems

Quadratic formula
Properties of Parabolas

Suitable Grade Level

Grades 9-10