Math Problem Statement

If f(x) = 3x - 5 and g(x) = 2x + 1, then the composite function (f o g)(x) is equal to:

Solution

To find the composite function (fg)(x)(f \circ g)(x), you need to substitute g(x)g(x) into f(x)f(x). In other words, you evaluate ff at g(x)g(x).

Given:

  • f(x)=3x5f(x) = 3x - 5
  • g(x)=2x+1g(x) = 2x + 1

We want to find f(g(x))f(g(x)). This means substituting g(x)=2x+1g(x) = 2x + 1 into f(x)f(x):

f(g(x))=f(2x+1)f(g(x)) = f(2x + 1)

Now, replace xx in f(x)=3x5f(x) = 3x - 5 with 2x+12x + 1:

f(2x+1)=3(2x+1)5f(2x + 1) = 3(2x + 1) - 5

Distribute the 3:

f(2x+1)=6x+35f(2x + 1) = 6x + 3 - 5

Simplify:

f(2x+1)=6x2f(2x + 1) = 6x - 2

So, the composite function (fg)(x)(f \circ g)(x) is:

(fg)(x)=6x2(f \circ g)(x) = 6x - 2

Would you like more details on composite functions or have any other questions?

Here are 5 related questions to explore further:

  1. What is the composite function (gf)(x)(g \circ f)(x)?
  2. How do you find the inverse of a composite function?
  3. What happens if you compose more than two functions, like (hfg)(x)(h \circ f \circ g)(x)?
  4. Can you graph composite functions and what do they look like?
  5. How do you solve composite functions if the output is known (e.g., (fg)(x)=10(f \circ g)(x) = 10)?

Tip: When working with composite functions, always follow the order of operations, starting from the inside function first.

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Math Problem Analysis

Mathematical Concepts

Algebra
Composite Functions
Function Substitution

Formulas

f(x) = 3x - 5
g(x) = 2x + 1
f(g(x)) = f(2x + 1) = 6x - 2

Theorems

Composite Function Theorem

Suitable Grade Level

Grades 9-11