Math Problem Statement

Which is the vertex of the quadratic function f(x) = 8x + 4x^2 - 2?

Solution

We are given the quadratic function f(x)=8x+4x22f(x) = 8x + 4x^2 - 2, and the question asks for the vertex of the function.

To find the vertex of a quadratic function f(x)=ax2+bx+cf(x) = ax^2 + bx + c, we can use the formula for the x-coordinate of the vertex: x=b2ax = \frac{-b}{2a} where aa is the coefficient of x2x^2 and bb is the coefficient of xx.

Step 1: Identify the coefficients

For the given function f(x)=4x2+8x2f(x) = 4x^2 + 8x - 2, we have:

  • a=4a = 4
  • b=8b = 8
  • c=2c = -2 (though cc is not needed to find the vertex)

Step 2: Apply the formula for the x-coordinate of the vertex

x=82×4=88=1x = \frac{-8}{2 \times 4} = \frac{-8}{8} = -1

Step 3: Find the y-coordinate by substituting x=1x = -1 back into the function

f(1)=4(1)2+8(1)2f(-1) = 4(-1)^2 + 8(-1) - 2 f(1)=4(1)82=482=6f(-1) = 4(1) - 8 - 2 = 4 - 8 - 2 = -6

Conclusion:

The vertex of the quadratic function is (1,6)(-1, -6).

So, the correct answer is (1,6)(-1, -6).

Let me know if you want more details on this. Here are some additional related questions:

  1. How do you find the axis of symmetry from a quadratic function?
  2. Can you explain the significance of the vertex in a parabola?
  3. How can you rewrite the given quadratic function in vertex form?
  4. What is the general shape of a parabola for a quadratic function with a positive aa?
  5. How would the graph change if the quadratic function was 4x2+8x2-4x^2 + 8x - 2?

Tip: The vertex form of a quadratic function is useful when you want to easily identify the vertex and the direction in which the parabola opens.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Vertex of a Parabola

Formulas

x = -b / (2a) for the x-coordinate of the vertex
f(x) = ax^2 + bx + c for a quadratic equation

Theorems

Vertex formula for a quadratic function

Suitable Grade Level

Grades 8-10