Math Problem Statement

Consider the functions f(x) = -5x + 3 and g(x) = 1/5(x - 3). (a) Find f(g(x)). (b) Find g(f(x)). (c) Determine whether the functions f and g are inverses of each other.

Solution

Let's solve each part of the question step by step. We have two functions defined as follows:

f(x)=5x+3f(x) = -5x + 3 g(x)=15(x3)g(x) = \frac{1}{5}(x - 3)

(a) Find f(g(x))f(g(x))

To find f(g(x))f(g(x)), we substitute g(x)g(x) into f(x)f(x): f(g(x))=f(15(x3))f(g(x)) = f\left(\frac{1}{5}(x - 3)\right) Now, substitute this expression into f(x)=5x+3f(x) = -5x + 3: f(15(x3))=5(15(x3))+3f\left(\frac{1}{5}(x - 3)\right) = -5\left(\frac{1}{5}(x - 3)\right) + 3 Simplify the expression: =(x3)+3= -(x - 3) + 3 =x+3+3= -x + 3 + 3 =x+6= -x + 6

So, f(g(x))=x+6f(g(x)) = -x + 6.

(b) Find g(f(x))g(f(x))

To find g(f(x))g(f(x)), we substitute f(x)f(x) into g(x)g(x): g(f(x))=g(5x+3)g(f(x)) = g(-5x + 3) Now, substitute this expression into g(x)=15(x3)g(x) = \frac{1}{5}(x - 3): g(5x+3)=15((5x+3)3)g(-5x + 3) = \frac{1}{5}((-5x + 3) - 3) Simplify the expression inside the parentheses: =15(5x)= \frac{1}{5}(-5x) =x= -x

So, g(f(x))=xg(f(x)) = -x.

(c) Determine whether the functions ff and gg are inverses of each other

Two functions ff and gg are inverses of each other if f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x.

From parts (a) and (b), we found: f(g(x))=x+6f(g(x)) = -x + 6 g(f(x))=xg(f(x)) = -x

Since neither f(g(x))=xf(g(x)) = x nor g(f(x))=xg(f(x)) = x, the functions ff and gg are not inverses of each other.

Would you like more details or have questions about any steps?

Further Questions

  1. How do we find the inverse of a function in general?
  2. What properties do inverse functions satisfy?
  3. Can you explain the steps in simplifying f(g(x))f(g(x))?
  4. What is the difference between composition of functions and inverse functions?
  5. How can we verify if a function is one-to-one?

Tip

When testing if two functions are inverses, remember to check both f(g(x))=xf(g(x)) = x and g(f(x))=xg(f(x)) = x; both conditions must be true for them to be inverses.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Inverse Functions

Formulas

f(g(x))
g(f(x))

Theorems

Definition of Inverse Functions

Suitable Grade Level

Grades 10-12