Quiz

If [tex]f(x)=\frac{x-1}{3}[/tex] and [tex]g(x)=3x+1[/tex], what is [tex](f \circ g)(x)[/tex]?

A. [tex](f \circ g)(x)=3x+1[/tex]
B. [tex](f \circ g)(x)=x-3[/tex]
C. [tex](f \circ g)(x)=3x[/tex]
D. [tex](f \circ g)(x)=x[/tex]



Answer :

To find [tex]\((f \circ g)(x)\)[/tex], we need to evaluate the composition of the functions [tex]\(f(x)\)[/tex] and [tex]\(g(x)\)[/tex]. In other words, we need to find [tex]\(f(g(x))\)[/tex], which means we will substitute [tex]\(g(x)\)[/tex] into [tex]\(f(x)\)[/tex].

First, let's write down the functions:

[tex]\[ f(x) = \frac{x-1}{3} \][/tex]
[tex]\[ g(x) = 3x + 1 \][/tex]

Now, we will substitute [tex]\(g(x)\)[/tex] into [tex]\(f(x)\)[/tex]:

[tex]\[ f(g(x)) = f(3x + 1) \][/tex]

Next, we replace [tex]\(x\)[/tex] in [tex]\(f(x)\)[/tex] with [tex]\(g(x)\)[/tex], which in this case is [tex]\(3x + 1\)[/tex]:

[tex]\[ f(3x + 1) = \frac{(3x + 1) - 1}{3} \][/tex]

Simplify within the parentheses:

[tex]\[ f(3x + 1) = \frac{3x + 1 - 1}{3} \][/tex]
[tex]\[ f(3x + 1) = \frac{3x}{3} \][/tex]

Finally, simplify the fraction:

[tex]\[ f(3x + 1) = x \][/tex]

Thus, the function [tex]\((f \circ g)(x) = f(g(x)) = x\)[/tex].

So, the correct answer is:
[tex]\[ (f \circ g)(x) = x \][/tex]