Math Problem Statement

Graph the function f(x) = 3x^2 + 6x. Plot the vertex. Then plot another point on the parabola. If you make a mistake, you can erase your parabola by selecting the second point and placing it on top of the first.

Solution

The given problem asks you to graph the function f(x)=3x2+6xf(x) = 3x^2 + 6x. Let's break it down step by step:

1. Identify the Vertex of the Parabola

The given function is in standard quadratic form:
f(x)=ax2+bx+cf(x) = ax^2 + bx + c
Here, a=3a = 3, b=6b = 6, and c=0c = 0.

The formula for the x-coordinate of the vertex is:
xvertex=b2ax_{\text{vertex}} = -\frac{b}{2a}
Substitute a=3a = 3 and b=6b = 6:
xvertex=62(3)=1x_{\text{vertex}} = -\frac{6}{2(3)} = -1

To find the y-coordinate, substitute x=1x = -1 into the function:
f(1)=3(1)2+6(1)=3(1)6=3f(-1) = 3(-1)^2 + 6(-1) = 3(1) - 6 = -3

So, the vertex is at (1,3)(-1, -3).

2. Plot Another Point on the Parabola

Choose another x-value near the vertex, for example, x=0x = 0.
Substitute x=0x = 0 into the function:
f(0)=3(0)2+6(0)=0f(0) = 3(0)^2 + 6(0) = 0
So, another point on the parabola is (0,0)(0, 0), which is also the y-intercept.

3. Draw the Parabola

  1. Plot the vertex (1,3)(-1, -3).
  2. Plot the second point (0,0)(0, 0).
  3. Since parabolas are symmetric, another point on the opposite side of the vertex can be reflected over x=1x = -1. For example, since (0,0)(0, 0) is 1 unit to the right of the vertex, the point (2,0)(-2, 0) will be 1 unit to the left of the vertex.

Final Points for Plotting

  • Vertex: (1,3)(-1, -3)
  • Point: (0,0)(0, 0)
  • Symmetric Point: (2,0)(-2, 0)

Would you like me to provide additional details or clarifications?


Related Questions:

  1. How do you convert a quadratic function to vertex form?
  2. What is the significance of the axis of symmetry in a parabola?
  3. How do the values of aa, bb, and cc in a quadratic function affect its graph?
  4. Can you determine the direction of a parabola from its equation? How?
  5. How would adding a constant to f(x)f(x) affect the graph?

Tip:

The vertex formula x=b2ax = -\frac{b}{2a} is always useful when dealing with quadratic functions in standard form!

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Vertex of a Parabola
Graphing Parabolas

Formulas

f(x) = ax^2 + bx + c
x_vertex = -b / (2a)

Theorems

Axis of Symmetry of a Parabola

Suitable Grade Level

Grades 9-11