Math Problem Statement

​Determine, without​ graphing, whether the given quadratic function has a maximum value or a minimum value and then find the value. f left parenthesis x right parenthesis equals 3 x squared plus 12 x minus 8 Question content area bottom Part 1 Does the quadratic function f have a minimum value or a maximum​ value? The function f has a maximum value. The function f has a minimum value. Your answer is correct. Part 2 What is this minimum or maximum​ value?    enter your response here

Solution

Step 1: Determine if the quadratic function has a minimum or maximum value

The given quadratic function is:
f(x)=3x2+12x8f(x) = 3x^2 + 12x - 8

For a quadratic function of the form f(x)=ax2+bx+cf(x) = ax^2 + bx + c:

  • If a>0a > 0, the parabola opens upward, and the function has a minimum value.
  • If a<0a < 0, the parabola opens downward, and the function has a maximum value.

Here, a=3>0a = 3 > 0, so the function has a minimum value.


Step 2: Find the minimum value

The minimum (or maximum) value of a quadratic function occurs at the vertex.
For a quadratic function f(x)=ax2+bx+cf(x) = ax^2 + bx + c, the xx-coordinate of the vertex is given by: x=b2ax = -\frac{b}{2a} For our function f(x)=3x2+12x8f(x) = 3x^2 + 12x - 8, we have:

  • a=3a = 3
  • b=12b = 12

Now, substitute into the vertex formula: x=122(3)=126=2x = -\frac{12}{2(3)} = -\frac{12}{6} = -2


Step 3: Find the function value at the vertex

Now that we know the xx-coordinate of the vertex is x=2x = -2, substitute it into the function to find the corresponding f(x)f(x) value: f(2)=3(2)2+12(2)8f(-2) = 3(-2)^2 + 12(-2) - 8 f(2)=3(4)+12(2)8=12248=20f(-2) = 3(4) + 12(-2) - 8 = 12 - 24 - 8 = -20

So, the minimum value of the function is: f(2)=20f(-2) = -20


Final Answer

  1. The function has a minimum value because the coefficient of x2x^2 is positive.
  2. The minimum value is 20-20.

Would you like further details or another example?


Here are 5 related questions you might consider:

  1. How do you determine if a quadratic function opens up or down?
  2. What is the vertex form of a quadratic function?
  3. How does completing the square help in finding the vertex?
  4. How do you find the axis of symmetry for a quadratic function?
  5. What happens to the graph if the value of aa is increased or decreased?

Tip: The vertex gives the turning point of a parabola, which is either its minimum or maximum depending on the coefficient of x2x^2.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Vertex of a Parabola

Formulas

Vertex formula for quadratic function: x = -b / (2a)
Function value at the vertex: f(x)

Theorems

Properties of Quadratic Functions
Vertex Theorem

Suitable Grade Level

Grades 9-10