Math Problem Statement

Let f(x)=2x+5 and g(x)=4x2+3x. After simplifying, (f∘g)(x)= 

Solution

To find (fg)(x)(f \circ g)(x), also written as f(g(x))f(g(x)), we substitute the expression for g(x)g(x) into f(x)f(x).

Step 1: Write out f(g(x))f(g(x))

We are given:

  • f(x)=2x+5f(x) = 2x + 5
  • g(x)=4x2+3xg(x) = 4x^2 + 3x

Now substitute g(x)g(x) into f(x)f(x): f(g(x))=f(4x2+3x)f(g(x)) = f(4x^2 + 3x)

Step 2: Apply f(x)=2x+5f(x) = 2x + 5 to g(x)g(x)

To do this, replace xx in f(x)f(x) with 4x2+3x4x^2 + 3x: f(g(x))=2(4x2+3x)+5f(g(x)) = 2(4x^2 + 3x) + 5

Step 3: Simplify the expression

Distribute the 2 across the terms inside the parentheses: f(g(x))=2(4x2)+2(3x)+5f(g(x)) = 2(4x^2) + 2(3x) + 5 f(g(x))=8x2+6x+5f(g(x)) = 8x^2 + 6x + 5

So, the simplified form of (fg)(x)(f \circ g)(x) is: (fg)(x)=8x2+6x+5(f \circ g)(x) = 8x^2 + 6x + 5

Would you like more details or have any questions?


Here are 5 related questions:

  1. How would you compute (gf)(x)(g \circ f)(x)?
  2. What is the domain of (fg)(x)(f \circ g)(x)?
  3. Can you graph the function (fg)(x)(f \circ g)(x)?
  4. How do the graphs of f(x)f(x) and g(x)g(x) differ?
  5. What happens if f(x)f(x) is a constant function instead?

Tip: When composing functions, always carefully substitute one function into the other and simplify step by step.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra
Polynomial Functions

Formulas

f(g(x)) = f(4x^2 + 3x)
f(x) = 2x + 5
g(x) = 4x^2 + 3x

Theorems

Function Composition

Suitable Grade Level

Grades 9-11