Math Problem Statement

why is x-8/3x-16 listed as the correct answer when 𝑓(π‘₯)=1π‘₯+2f(x)=1x+2 and π‘”(π‘₯)=π‘₯/π‘₯βˆ’8 and im evaluating f(g(x))

Solution

Let's go step by step to evaluate f(g(x))f(g(x)) when f(x)=1x+2f(x) = \frac{1}{x+2} and g(x)=xxβˆ’8g(x) = \frac{x}{x-8}.

Step 1: Substitute g(x)g(x) into f(x)f(x)

To find f(g(x))f(g(x)), we substitute the expression for g(x)g(x) into f(x)f(x). This means wherever there is an xx in the function f(x)f(x), we replace it with g(x)g(x).

f(g(x))=1g(x)+2f(g(x)) = \frac{1}{g(x) + 2}

Step 2: Replace g(x)g(x) with xxβˆ’8\frac{x}{x-8}

Now, substitute the expression for g(x)g(x) into the equation for f(g(x))f(g(x)):

f(g(x))=1xxβˆ’8+2f(g(x)) = \frac{1}{\frac{x}{x-8} + 2}

Step 3: Simplify the expression

We need to simplify the denominator. First, express the "2" as a fraction with a common denominator:

f(g(x))=1xxβˆ’8+2(xβˆ’8)xβˆ’8f(g(x)) = \frac{1}{\frac{x}{x-8} + \frac{2(x-8)}{x-8}} f(g(x))=1x+2(xβˆ’8)xβˆ’8f(g(x)) = \frac{1}{\frac{x + 2(x-8)}{x-8}} Now simplify the numerator:

x+2(xβˆ’8)=x+2xβˆ’16=3xβˆ’16x + 2(x-8) = x + 2x - 16 = 3x - 16

So the expression becomes:

f(g(x))=13xβˆ’16xβˆ’8f(g(x)) = \frac{1}{\frac{3x - 16}{x-8}}

Step 4: Simplify further

Now, simplify the overall expression:

f(g(x))=13xβˆ’16xβˆ’8=xβˆ’83xβˆ’16f(g(x)) = \frac{1}{\frac{3x - 16}{x-8}} = \frac{x - 8}{3x - 16}

Final Answer:

Thus, the simplified expression for f(g(x))f(g(x)) is:

f(g(x))=xβˆ’83xβˆ’16f(g(x)) = \frac{x - 8}{3x - 16}

This explains why the expression xβˆ’83xβˆ’16\frac{x - 8}{3x - 16} is listed as the correct answer.

Would you like any further clarification or more details?

Related Questions:

  1. How do you evaluate composite functions like f(g(x))f(g(x)) for more complex functions?
  2. What are the typical domains for functions like f(x)=1x+2f(x) = \frac{1}{x+2} and ( g(x) = \frac

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Composite Functions
Rational Functions
Algebraic Simplification

Formulas

f(g(x)) = f(g(x)) = 1 / (g(x) + 2)
g(x) = x / (x - 8)

Theorems

Composite Function Theorem

Suitable Grade Level

Grades 10-12