High School

Dear beloved readers, welcome to our website! We hope your visit here brings you valuable insights and meaningful inspiration. Thank you for taking the time to stop by and explore the content we've prepared for you.
------------------------------------------------ The function [tex]f(x)=-\frac{1}{4} x-3[/tex] is defined for values of [tex]x[/tex] on the interval [tex]-4 < x < 16[/tex].

What are the domain and range of [tex]f(x)[/tex]?

A. Domain: all real numbers; Range: all real numbers

B. Domain: [tex]-4 < x < 16[/tex]; Range: [tex]4 < f(x) < 7[/tex]

C. Domain: [tex]-4 < x < 16[/tex]; Range: [tex]-7 < f(x) < -2[/tex]

D. Domain: [tex]0 < x < 4[/tex]; Range: [tex]-4 < f(x) < -7[/tex]

Answer :

Let's break down the problem to find the domain and range of the function [tex]\( f(x) = -\frac{1}{4} x - 3 \)[/tex] given the interval [tex]\( -4 < x < 16 \)[/tex].

Domain:
The domain specifies the set of input values (x-values) for which the function is defined. According to the problem, the domain is given as [tex]\( -4 < x < 16 \)[/tex]. So we clearly omit options A and D.

Range:
To find the range, we need to determine the set of output values (y-values) that the function [tex]\( f(x) \)[/tex] can take when [tex]\( x \)[/tex] is within the given interval.

1. First, calculate the value of [tex]\( f(x) \)[/tex] at the endpoints of the interval:
- At [tex]\( x = -4 \)[/tex]:
[tex]\[
f(-4) = -\frac{1}{4}(-4) - 3 = 1 - 3 = -2
\][/tex]

- At [tex]\( x = 16 \)[/tex]:
[tex]\[
f(16) = -\frac{1}{4}(16) - 3 = -4 - 3 = -7
\][/tex]

2. Observing these values shows us that [tex]\( f(-4) = -2 \)[/tex] is the highest point and [tex]\( f(16) = -7 \)[/tex] is the lowest point.

3. Therefore, the range of the function [tex]\( f(x) \)[/tex] as [tex]\( x \)[/tex] goes from -4 to 16 is [tex]\( -2 > f(x) > -7 \)[/tex], which translates to the interval [tex]\( -7 < f(x) < -2 \)[/tex].

Given these observations, the correct choice is:

C. domain: [tex]\(-4 < x < 16\)[/tex]; range: [tex]\(-7 < f(x) < -2\)[/tex]