Math Problem Statement

f(x)=x²-2x+3 g(x)=5x+2 (fog)(x)

Solution

To find (fg)(x)(f \circ g)(x), also written as (fog)(x)(fog)(x), we need to substitute the function g(x)g(x) into the function f(x)f(x).

Given:

  • f(x)=x22x+3f(x) = x^2 - 2x + 3
  • g(x)=5x+2g(x) = 5x + 2

We substitute g(x)g(x) into f(x)f(x): (fg)(x)=f(g(x))=f(5x+2)(f \circ g)(x) = f(g(x)) = f(5x + 2)

Now, substitute 5x+25x + 2 for xx in f(x)f(x): f(5x+2)=(5x+2)22(5x+2)+3f(5x + 2) = (5x + 2)^2 - 2(5x + 2) + 3

Now, expand the terms: (5x+2)2=25x2+20x+4(5x + 2)^2 = 25x^2 + 20x + 4 2(5x+2)=10x4-2(5x + 2) = -10x - 4 So, the equation becomes: f(5x+2)=25x2+20x+410x4+3f(5x + 2) = 25x^2 + 20x + 4 - 10x - 4 + 3

Now simplify: f(5x+2)=25x2+(20x10x)+(44+3)f(5x + 2) = 25x^2 + (20x - 10x) + (4 - 4 + 3) f(5x+2)=25x2+10x+3f(5x + 2) = 25x^2 + 10x + 3

Thus, (fg)(x)=25x2+10x+3(f \circ g)(x) = 25x^2 + 10x + 3.

Would you like any additional details or have any questions?

Here are five related questions:

  1. What is (gf)(x)(g \circ f)(x)?
  2. How do you find the inverse of f(x)f(x) and g(x)g(x)?
  3. What is the domain of (fg)(x)(f \circ g)(x)?
  4. How would you find (fg)(2)(f \circ g)(2)?
  5. How do you determine if f(x)f(x) and g(x)g(x) are one-to-one functions?

Tip: When composing functions, always substitute the entire second function into the first, and simplify carefully!

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Math Problem Analysis

Mathematical Concepts

Algebra
Function Composition
Quadratic Functions

Formulas

f(x) = x^2 - 2x + 3
g(x) = 5x + 2
(f ∘ g)(x) = f(g(x))

Theorems

Function Composition

Suitable Grade Level

Grades 9-12