The quadratic functions f(x) and g(x) are described as follows:

f(x) = −8x2 + 7


x g(x)
0 0
1 2
2 6
3 2
4 0


Which of the following statements best compares the maximum value of the two functions?
The maximum value is the same for both functions.
f(x) has a greater maximum value than g(x).
g(x) has a greater maximum value than f(x).
The maximum values cannot be determined.

Respuesta :

Given:

f(x) and g(x) are two quadratic functions.

[tex]f(x)=-8x^2-7[/tex]

The table of values for the function g(x) is given.

To find:

The statement that best compares the maximum value of the two functions.

Solution:

We have,

[tex]f(x)=-8x^2-7[/tex]

Here, the leading coefficient is -8 which is a negative number. So, the function f(x) represents a downward parabola.

We know that the vertex of a downward parabola is the point of maxima.

The vertex of a quadratic function [tex]f(x)=ax^2+bx+c[/tex] is:

[tex]Vertex=\left(\dfrac{-b}{2a},f(-\dfrac{b}{2a})\right)[/tex]

In the given function, [tex]a=-8,b=0,c=-7[/tex].

[tex]-\dfrac{b}{2a}=-\dfrac{0}{2(-8)}[/tex]

[tex]-\dfrac{b}{2a}=0[/tex]

Putting [tex]x=0[/tex] in the given function, we get

[tex]f(0)=-8(0)^2-7[/tex]

[tex]f(0)=-7[/tex]

So, the vertex of the function f(x) is at (0,-7). It means the maximum value of the function f(x) is -7.

From the table of g(x) it is clear that the maximum value of the function g(x) is 6.

Since [tex]6>-7[/tex], therefore g(x) has a greater maximum value than f(x).

Hence, the correct option is C.

Answer: the other answer is wrong the right one is

f(x) has a greater maximum value than g(x).

Step-by-step explanation: