Math Problem Statement

(g o f) if f(x)=3x + 4 , g(x)=2x - 3

Solution

The composition of functions (gf)(x)(g \circ f)(x) means you substitute the function f(x)f(x) into g(x)g(x).

Given:

  • f(x)=3x+4f(x) = 3x + 4
  • g(x)=2x3g(x) = 2x - 3

Now, let's compute g(f(x))g(f(x)):

(gf)(x)=g(f(x))=g(3x+4)(g \circ f)(x) = g(f(x)) = g(3x + 4)

Substitute 3x+43x + 4 into g(x)g(x):

g(3x+4)=2(3x+4)3g(3x + 4) = 2(3x + 4) - 3

Simplify:

=2(3x)+2(4)3= 2(3x) + 2(4) - 3 =6x+83= 6x + 8 - 3 =6x+5= 6x + 5

So, (gf)(x)=6x+5(g \circ f)(x) = 6x + 5.

Would you like further details or have any questions?

Here are 5 related questions to consider:

  1. What is (fg)(x)(f \circ g)(x)?
  2. How would you solve (gf)(2)(g \circ f)(2)?
  3. If g(x)=x21g(x) = x^2 - 1, how would that change (gf)(x)(g \circ f)(x)?
  4. What is the domain of g(f(x))g(f(x))?
  5. How does the order of function composition affect the result?

Tip: Always check the domain of the inner function when composing functions!

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Math Problem Analysis

Mathematical Concepts

Function Composition
Linear Functions
Algebra

Formulas

g(f(x)) = g(3x + 4) = 2(3x + 4) - 3

Theorems

Function Composition

Suitable Grade Level

Grades 9-11