Watch the video and show examples.

Determine whether the quadratic function shown below has a minimum or maximum, then determine the minimum or maximum value of the function.

[tex]f(x) = -2(x+6)(x+4)[/tex]

Answer Attempt 1 out of 2:

The [tex]\(\square\)[/tex] value is [tex]\(\square\)[/tex].



Answer :

Sure, let's analyze the given quadratic function [tex]\( f(x) = -2(x + 6)(x + 4) \)[/tex].

### Step 1: Expand the Function
First, expand [tex]\( f(x) \)[/tex] to write it in standard quadratic form [tex]\( ax^2 + bx + c \)[/tex]:
[tex]\[ f(x) = -2(x + 6)(x + 4) \][/tex]
Using the distributive property (also known as the FOIL method for binomials):
[tex]\[ (x + 6)(x + 4) = x^2 + 4x + 6x + 24 = x^2 + 10x + 24 \][/tex]
So,
[tex]\[ f(x) = -2(x^2 + 10x + 24) = -2x^2 - 20x - 48 \][/tex]

### Step 2: Determine the Vertex
The standard form of a quadratic function is [tex]\( ax^2 + bx + c \)[/tex]. In our case, [tex]\( a = -2 \)[/tex], [tex]\( b = -20 \)[/tex], and [tex]\( c = -48 \)[/tex].

For a quadratic function [tex]\( ax^2 + bx + c \)[/tex], the x-coordinate of the vertex (maximum or minimum point) is given by:
[tex]\[ x = -\frac{b}{2a} \][/tex]

Plugging in our values of [tex]\( a \)[/tex] and [tex]\( b \)[/tex]:
[tex]\[ x = -\frac{-20}{2 \cdot -2} = \frac{20}{-4} = -5 \][/tex]

### Step 3: Determine the Nature of the Vertex
A quadratic function [tex]\( ax^2 + bx + c \)[/tex] has a:
- Maximum if [tex]\( a < 0 \)[/tex]
- Minimum if [tex]\( a > 0 \)[/tex]

Since [tex]\( a = -2 \)[/tex] in our function and it is negative, the function has a maximum.

### Step 4: Calculate the Maximum Value
To find the maximum value of the function, we need to evaluate [tex]\( f(x) \)[/tex] at the vertex:
[tex]\[ f(-5) = -2(-5 + 6)(-5 + 4) \][/tex]

Simplify within the parentheses:
[tex]\[ f(-5) = -2(1)(-1) = -2 \cdot -1 = 2 \][/tex]

### Conclusion
The quadratic function [tex]\( f(x) = -2(x + 6)(x + 4) \)[/tex] has a maximum value, and the maximum value is [tex]\( \boxed{2} \)[/tex].