At Westonci.ca, we provide clear, reliable answers to all your questions. Join our vibrant community and get the solutions you need. Ask your questions and receive accurate answers from professionals with extensive experience in various fields on our platform. Join our Q&A platform to connect with experts dedicated to providing accurate answers to your questions in various fields.

Select the function that represents a parabola with zeros at [tex]x=-2[/tex] and [tex]x=4[/tex], and a [tex]y[/tex]-intercept at [tex](0,-16)[/tex].

A. [tex]f(x)=2x^2+4x-16[/tex]
B. [tex]f(x)=x^2-2x-8[/tex]
C. [tex]f(x)=x^2+2x-8[/tex]
D. [tex]f(x)=2x^2-4x-16[/tex]

Sagot :

To determine which function represents a parabola with zeros at [tex]\( x = -2 \)[/tex] and [tex]\( x = 4 \)[/tex], and a y-intercept at [tex]\( (0, -16) \)[/tex], we need to verify these conditions for each given function.

### Checking Zero Points

1. Function A: [tex]\( f(x) = 2x^2 + 4x - 16 \)[/tex]
- Calculate [tex]\( f(-2) \)[/tex]:
[tex]\[ f(-2) = 2(-2)^2 + 4(-2) - 16 = 2(4) - 8 - 16 = 8 - 8 - 16 = -16 \neq 0 \][/tex]
- Calculate [tex]\( f(4) \)[/tex]:
[tex]\[ f(4) = 2(4)^2 + 4(4) - 16 = 2(16) + 16 - 16 = 32 + 16 - 16 = 32 \neq 0 \][/tex]
- Thus, Function A does not have zeros at [tex]\( x = -2 \)[/tex] and [tex]\( x = 4 \)[/tex].

2. Function B: [tex]\( f(x) = x^2 - 2x - 8 \)[/tex]
- Calculate [tex]\( f(-2) \)[/tex]:
[tex]\[ f(-2) = (-2)^2 - 2(-2) - 8 = 4 + 4 - 8 = 0 \][/tex]
- Calculate [tex]\( f(4) \)[/tex]:
[tex]\[ f(4) = (4)^2 - 2(4) - 8 = 16 - 8 - 8 = 0 \][/tex]
- Thus, Function B has zeros at [tex]\( x = -2 \)[/tex] and [tex]\( x = 4 \)[/tex].

3. Function C: [tex]\( f(x) = x^2 + 2x - 8 \)[/tex]
- Calculate [tex]\( f(-2) \)[/tex]:
[tex]\[ f(-2) = (-2)^2 + 2(-2) - 8 = 4 - 4 - 8 = -8 \neq 0 \][/tex]
- Calculate [tex]\( f(4) \)[/tex]:
[tex]\[ f(4) = (4)^2 + 2(4) - 8 = 16 + 8 - 8 = 16 \neq 0 \][/tex]
- Thus, Function C does not have zeros at [tex]\( x = -2 \)[/tex] and [tex]\( x = 4 \)[/tex].

4. Function D: [tex]\( f(x) = 2x^2 - 4x - 16 \)[/tex]
- Calculate [tex]\( f(-2) \)[/tex]:
[tex]\[ f(-2) = 2(-2)^2 - 4(-2) - 16 = 2(4) + 8 - 16 = 8 + 8 - 16 = 0 \][/tex]
- Calculate [tex]\( f(4) \)[/tex]:
[tex]\[ f(4) = 2(4)^2 - 4(4) - 16 = 2(16) - 16 - 16 = 32 - 32 = 0 \][/tex]
- Thus, Function D has zeros at [tex]\( x = -2 \)[/tex] and [tex]\( x = 4 \)[/tex].

### Checking the Y-Intercept

To find the y-intercept, we substitute [tex]\( x = 0 \)[/tex] into each function and see if the result equals -16:

1. Function A: [tex]\( f(x) = 2x^2 + 4x - 16 \)[/tex]
[tex]\[ f(0) = 2(0)^2 + 4(0) - 16 = -16 \][/tex]
- Function A has a y-intercept at [tex]\( (0, -16) \)[/tex].

2. Function B: [tex]\( f(x) = x^2 - 2x - 8 \)[/tex]
[tex]\[ f(0) = (0)^2 - 2(0) - 8 = -8 \][/tex]
- Function B does not have a y-intercept at [tex]\( (0, -16) \)[/tex].

3. Function C: [tex]\( f(x) = x^2 + 2x - 8 \)[/tex]
[tex]\[ f(0) = (0)^2 + 2(0) - 8 = -8 \][/tex]
- Function C does not have a y-intercept at [tex]\( (0, -16) \)[/tex].

4. Function D: [tex]\( f(x) = 2x^2 - 4x - 16 \)[/tex]
[tex]\[ f(0) = 2(0)^2 - 4(0) - 16 = -16 \][/tex]
- Function D has a y-intercept at [tex]\( (0, -16) \)[/tex].

### Conclusion
Among the functions, only Function D: [tex]\( f(x) = 2x^2 - 4x - 16 \)[/tex] has the zeros [tex]\( x = -2 \)[/tex] and [tex]\( x = 4 \)[/tex], and the y-intercept at [tex]\( (0, -16) \)[/tex].

Therefore, the correct function is:
[tex]\[ \boxed{2} \][/tex]