Math Problem Statement

Express your answer as a polynomial in standard form.

f, of, x, equals, minus, 3, x, plus, 12

f(x)=

−3x+12

g, of, x, equals, 3, x, squared, minus, 6, x, minus, 6

g(x)=

3x2−6x−6

Find: , left parenthesis, f, circle, g, right parenthesis, left parenthesis, x, right parenthesis

Find: (fg)(x)

Solution

To find (fg)(x)(f \circ g)(x), we need to compute the composition of functions f(x)f(x) and g(x)g(x), which means substituting g(x)g(x) into f(x)f(x).

Given:

  • f(x)=3x+12f(x) = -3x + 12
  • g(x)=3x26x6g(x) = 3x^2 - 6x - 6

To find (fg)(x)(f \circ g)(x), we replace xx in f(x)f(x) with g(x)g(x). So we have: (fg)(x)=f(g(x))=f(3x26x6)(f \circ g)(x) = f(g(x)) = f(3x^2 - 6x - 6)

Substitute g(x)g(x) into f(x)f(x): f(g(x))=3(3x26x6)+12f(g(x)) = -3(3x^2 - 6x - 6) + 12

Now distribute the 3-3: f(g(x))=9x2+18x+18+12f(g(x)) = -9x^2 + 18x + 18 + 12

Combine like terms: f(g(x))=9x2+18x+30f(g(x)) = -9x^2 + 18x + 30

Thus, the composition (fg)(x)(f \circ g)(x) is: (fg)(x)=9x2+18x+30(f \circ g)(x) = -9x^2 + 18x + 30

Would you like more details or have any questions about this? Here are five related questions to explore further:

  1. How do you find the composition of functions in general?
  2. What is the difference between (fg)(x)(f \circ g)(x) and (gf)(x)(g \circ f)(x)?
  3. Can you determine the degree of a polynomial after composition?
  4. What happens when both functions are quadratic, not linear like f(x)f(x)?
  5. How can we determine if the composition of two functions is one-to-one?

Tip: Always simplify the expression after substitution to make sure the function is in standard polynomial form.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Function Composition
Polynomials
Algebra

Formulas

(f ∘ g)(x) = f(g(x))

Theorems

Polynomial Standard Form

Suitable Grade Level

Grades 10-12