Math Problem Statement

The function g(x) = -2x2 - 8x - 6 has a maximum or minimum value. What is the maximum or minimum value of g(x)?

Question 30Answer

a.

-6

b.

-8

c.

-10

d.

2

Solution

The function given is g(x)=2x28x6g(x) = -2x^2 - 8x - 6.

This is a quadratic function of the form g(x)=ax2+bx+cg(x) = ax^2 + bx + c, where a=2a = -2, b=8b = -8, and c=6c = -6.

To determine whether the function has a maximum or minimum value, we need to examine the coefficient aa. Since aa is negative (a=2a = -2), the parabola opens downwards, meaning the function has a maximum value.

The maximum or minimum value of a quadratic function occurs at the vertex of the parabola. The xx-coordinate of the vertex can be found using the formula:

x=b2ax = \frac{-b}{2a}

Substituting the values of aa and bb:

x=(8)2(2)=84=2x = \frac{-(-8)}{2(-2)} = \frac{8}{-4} = -2

Now, substitute x=2x = -2 back into the function to find the corresponding yy-value:

g(2)=2(2)28(2)6g(-2) = -2(-2)^2 - 8(-2) - 6

g(2)=2(4)+166g(-2) = -2(4) + 16 - 6

g(2)=8+166=2g(-2) = -8 + 16 - 6 = 2

So, the maximum value of g(x)g(x) is 2.

The correct answer is:

d. 2

Would you like more details or have any questions about this problem? Here are some related questions:

  1. How do you determine the vertex of a quadratic function?
  2. What does the sign of the leading coefficient indicate about the graph of a quadratic function?
  3. Can a quadratic function have both a maximum and minimum value?
  4. How do you complete the square to find the vertex form of a quadratic function?
  5. How can you find the axis of symmetry for a quadratic function?
  6. What are the effects of changing the coefficient aa in a quadratic function?
  7. How do you determine if a quadratic equation has real roots?
  8. What is the significance of the discriminant in quadratic equations?

Tip: For any quadratic function, the vertex formula x=b2ax = \frac{-b}{2a} quickly gives you the xx-value at which the function reaches its maximum or minimum.

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Vertex of a Parabola
Maximum and Minimum Values

Formulas

Quadratic function formula g(x) = ax^2 + bx + c
Vertex formula x = -b/(2a)

Theorems

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Suitable Grade Level

Grades 9-12