Questions: Functions
Evaluating functions: Absolute value, rational, radical
The functions f, g, and h are defined as follows.
f(x) = x / (4 + x^2) g(x) = sqrt(3x + 9) h(x) = -12 + 9x
Find f(-4), g(2), and h(-1/3).
Simplify your answers as much as possible.
f(-4) =
g(2) =
h(-1/3) =
Transcript text: Functions
Evaluating functions: Absolute value, rational, radical
The functions $f, g$, and $h$ are defined as follows.
\[
f(x)=\frac{x}{4+x^{2}} \quad g(x)=\sqrt{3 x+9} \quad h(x)=-12+|9 x|
\]
Find $f(-4), g(2)$, and $h\left(-\frac{1}{3}\right)$.
Simplify your answers as much as possible.
\[
\begin{array}{r}
f(-4)= \\
g(2)= \\
h\left(-\frac{1}{3}\right)=
\end{array}
\]
Solution
Solution Steps
Step 1: Calculate \( f(-4) \)
The function \( f(x) \) is defined as:
\[
f(x) = \frac{x}{4 + x^2}
\]
Substitute \( x = -4 \) into the function:
\[
f(-4) = \frac{-4}{4 + (-4)^2} = \frac{-4}{4 + 16} = \frac{-4}{20} = -\frac{1}{5}
\]
Step 2: Calculate \( g(2) \)
The function \( g(x) \) is defined as:
\[
g(x) = \sqrt{3x + 9}
\]
Substitute \( x = 2 \) into the function:
\[
g(2) = \sqrt{3(2) + 9} = \sqrt{6 + 9} = \sqrt{15}
\]