Math Problem Statement

For ​f(x)equalsxplus5 and ​g(x)equals2xplus3​, find the following functions. a. left parenthesis f circle g right parenthesis left parenthesis x right parenthesis​; b. left parenthesis g circle f right parenthesis left parenthesis x right parenthesis​; c. left parenthesis f circle g right parenthesis left parenthesis 2 right parenthesis​; d. left parenthesis g circle f right parenthesis left parenthesis 2 right parenthesis Question content area bottom Part 1 a. left parenthesis f circle g right parenthesis left parenthesis x right parenthesisequals    enter your response here ​(Simplify your​ answer.) Part 2 b. left parenthesis g circle f right parenthesis left parenthesis x right parenthesisequals    enter your response here ​(Simplify your​ answer.) Part 3 c. left parenthesis f circle g right parenthesis left parenthesis 2 right parenthesisequals    enter your response here Part 4 d. left parenthesis g circle f right parenthesis left parenthesis 2 right parenthesisequals    enter your response here

Solution

Let's solve the problem step by step:

Given functions:

  • f(x)=x+5f(x) = x + 5
  • g(x)=2x+3g(x) = 2x + 3

We need to find:

  1. (fg)(x)(f \circ g)(x)
  2. (gf)(x)(g \circ f)(x)
  3. (fg)(2)(f \circ g)(2)
  4. (gf)(2)(g \circ f)(2)

Part 1: (fg)(x)(f \circ g)(x)

The composition (fg)(x)(f \circ g)(x) means f(g(x))f(g(x)). Substitute g(x)=2x+3g(x) = 2x + 3 into f(x)=x+5f(x) = x + 5: f(g(x))=f(2x+3)=(2x+3)+5=2x+8f(g(x)) = f(2x + 3) = (2x + 3) + 5 = 2x + 8

So, (fg)(x)=2x+8(f \circ g)(x) = 2x + 8.


Part 2: (gf)(x)(g \circ f)(x)

The composition (gf)(x)(g \circ f)(x) means g(f(x))g(f(x)). Substitute f(x)=x+5f(x) = x + 5 into g(x)=2x+3g(x) = 2x + 3: g(f(x))=g(x+5)=2(x+5)+3=2x+10+3=2x+13g(f(x)) = g(x + 5) = 2(x + 5) + 3 = 2x + 10 + 3 = 2x + 13

So, (gf)(x)=2x+13(g \circ f)(x) = 2x + 13.


Part 3: (fg)(2)(f \circ g)(2)

From Part 1, (fg)(x)=2x+8(f \circ g)(x) = 2x + 8. Substitute x=2x = 2: (fg)(2)=2(2)+8=4+8=12(f \circ g)(2) = 2(2) + 8 = 4 + 8 = 12

So, (fg)(2)=12(f \circ g)(2) = 12.


Part 4: (gf)(2)(g \circ f)(2)

From Part 2, (gf)(x)=2x+13(g \circ f)(x) = 2x + 13. Substitute x=2x = 2: (gf)(2)=2(2)+13=4+13=17(g \circ f)(2) = 2(2) + 13 = 4 + 13 = 17

So, (gf)(2)=17(g \circ f)(2) = 17.


Final Answers:

a. (fg)(x)=2x+8(f \circ g)(x) = 2x + 8
b. (gf)(x)=2x+13(g \circ f)(x) = 2x + 13
c. (fg)(2)=12(f \circ g)(2) = 12
d. (gf)(2)=17(g \circ f)(2) = 17


Do you want more details or have any questions?
Here are 5 related questions to explore further:

  1. What is the domain of (fg)(x)(f \circ g)(x) and (gf)(x)(g \circ f)(x)?
  2. How does the composition of functions differ when f(x)f(x) and g(x)g(x) are swapped?
  3. Can we find the inverse of (fg)(x)(f \circ g)(x)?
  4. What happens if f(x)=x2f(x) = x^2 and g(x)=xg(x) = \sqrt{x}?
  5. How would (fg)(x)(f \circ g)(x) look if g(x)=x3g(x) = x - 3?

Tip: Always simplify inside parentheses first when working with compositions!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Function Composition
Algebra

Formulas

(f ∘ g)(x) = f(g(x))
(g ∘ f)(x) = g(f(x))

Theorems

Composition of Functions

Suitable Grade Level

Grades 9-11