Math Problem Statement

Let the functions f(x) = 5x - 3 and g(x) = 2x - 7 be given. Evaluate (f ∘ g)(3).

Solution

The problem asks to evaluate (fg)(3)(f \circ g)(3), which is the composition of the two functions f(x)f(x) and g(x)g(x), without finding an explicit equation for the composition.

Given:

  • f(x)=5x3f(x) = 5x - 3
  • g(x)=2x7g(x) = 2x - 7

We need to follow these steps:

  1. First, evaluate g(3)g(3) by substituting x=3x = 3 into the equation for g(x)g(x): g(3)=2(3)7=67=1g(3) = 2(3) - 7 = 6 - 7 = -1

  2. Next, use the result g(3)=1g(3) = -1 as the input for the function f(x)f(x). So now, we evaluate f(1)f(-1): f(1)=5(1)3=53=8f(-1) = 5(-1) - 3 = -5 - 3 = -8

Therefore, (fg)(3)=8(f \circ g)(3) = -8.

Let me know if you'd like more details or have further questions.

Here are 5 related questions for practice:

  1. What is (gf)(3)(g \circ f)(3) using the same functions?
  2. What is g(f(2))g(f(2)) with the same given functions?
  3. How do you find the inverse of f(x)=5x3f(x) = 5x - 3?
  4. How do you determine if fgf \circ g is a one-to-one function?
  5. Can you describe the steps to graph the composition f(g(x))f(g(x))?

Tip: When working with function compositions, always evaluate the inner function first, then substitute its output into the outer function.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra

Formulas

f(g(x)) = f(2x - 7)
f(x) = 5x - 3
g(x) = 2x - 7

Theorems

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Suitable Grade Level

Grades 9-12