Math Problem Statement

If f(x) = 3x - 5 and g(x) = x - 9, which expression is equivalent to (f o g)(x)?

Solution

To solve (fg)(x)(f \circ g)(x), which is the composition of the functions f(x)=3x5f(x) = 3x - 5 and g(x)=x9g(x) = x - 9, follow these steps:

Step 1: Understand function composition.

The composition (fg)(x)(f \circ g)(x) means that we apply g(x)g(x) first, and then use the result as the input to f(x)f(x). In other words: (fg)(x)=f(g(x))(f \circ g)(x) = f(g(x))

Step 2: Substitute g(x)g(x) into f(x)f(x).

Since g(x)=x9g(x) = x - 9, substitute this expression into f(x)f(x): f(g(x))=f(x9)f(g(x)) = f(x - 9)

Now, recall that f(x)=3x5f(x) = 3x - 5. Replace xx in f(x)f(x) with x9x - 9: f(x9)=3(x9)5f(x - 9) = 3(x - 9) - 5

Step 3: Simplify the expression.

Simplify the expression: 3(x9)5=3x275=3x323(x - 9) - 5 = 3x - 27 - 5 = 3x - 32

Thus, the expression equivalent to (fg)(x)(f \circ g)(x) is: (fg)(x)=3x32(f \circ g)(x) = 3x - 32

Would you like more details or have any questions?

Related Questions:

  1. What would (gf)(x)(g \circ f)(x) look like with the same functions?
  2. How do you evaluate (fg)(2)(f \circ g)(2)?
  3. What happens if you change the functions to non-linear forms, like f(x)=x2f(x) = x^2?
  4. Can you find the domain of the composed function (fg)(x)(f \circ g)(x)?
  5. How would this composition work if g(x)g(x) was a trigonometric function?

Tip:

When performing function composition, always start by substituting the inner function's output as the input to the outer function, and carefully simplify the result.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra

Formulas

f(g(x)) = f(x - 9)
f(x) = 3x - 5

Theorems

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Suitable Grade Level

Grades 9-11