If [tex]$f(x)=\frac{x-3}{x}$[/tex], [tex]$g(x)=x+3$[/tex], and [tex]$h(x)=2x+1$[/tex], what is [tex]$(g \circ h \circ f)(x)$[/tex]?

A. [tex]$(g \circ h \circ f)(x)=\frac{3x-6}{x}$[/tex]
B. [tex]$(g \circ h \circ f)(x)=\frac{6x-6}{x}$[/tex]
C. [tex]$(g \circ h \circ f)(x)=\frac{2x+4}{2x+7}$[/tex]
D. [tex]$(g \circ h \circ f)(x)=\frac{8x+1}{2x+1}$[/tex]



Answer :

To find [tex]\((g \circ h \circ f)(x)\)[/tex], we need to perform the composition of the functions [tex]\(f\)[/tex], [tex]\(h\)[/tex], and [tex]\(g\)[/tex] in that order. This means we apply [tex]\(f\)[/tex] first, then [tex]\(h\)[/tex], and finally [tex]\(g\)[/tex].

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

2. Compute [tex]\(h(f(x))\)[/tex]:
Substitute [tex]\(f(x)\)[/tex] into [tex]\(h\)[/tex]:
[tex]\[ h(f(x)) = h\left(\frac{x - 3}{x}\right) \][/tex]
Given [tex]\(h(t) = 2t + 1\)[/tex], where [tex]\(t\)[/tex] is the input,
[tex]\[ h\left(\frac{x - 3}{x}\right) = 2 \left(\frac{x - 3}{x}\right) + 1 \][/tex]
Distribute the 2:
[tex]\[ = \frac{2(x - 3)}{x} + 1 \][/tex]
Combine the terms over a common denominator:
[tex]\[ = \frac{2(x - 3) + x}{x} = \frac{2x - 6 + x}{x} = \frac{3x - 6}{x} \][/tex]

3. Compute [tex]\(g(h(f(x)))\)[/tex]:
Substitute [tex]\(h(f(x))\)[/tex] into [tex]\(g\)[/tex]:
[tex]\[ g\left(h(f(x))\right) = g\left(\frac{3x - 6}{x}\right) \][/tex]
Given [tex]\(g(t) = t + 3\)[/tex],
[tex]\[ g\left(\frac{3x - 6}{x}\right) = \left(\frac{3x - 6}{x}\right) + 3 \][/tex]
Express [tex]\(3\)[/tex] with a common denominator of [tex]\(x\)[/tex]:
[tex]\[ = \frac{3x - 6}{x} + \frac{3x}{x} \][/tex]
Combine the terms:
[tex]\[ = \frac{3x - 6 + 3x}{x} = \frac{6x - 6}{x} \][/tex]

So, [tex]\((g \circ h \circ f)(x) = \frac{6x - 6}{x}\)[/tex].

This corresponds to the second option:
[tex]\[ (g \circ h \circ f)(x) = \frac{6 x-6}{x} \][/tex]