If [tex]h(x)=5+x[/tex] and [tex]k(x)=\frac{1}{x}[/tex], which expression is equivalent to [tex](k \circ h)(x)[/tex]?

A. [tex]\frac{5+x}{x}[/tex]
B. [tex]\frac{1}{5+x}[/tex]
C. [tex]5+\frac{1}{x}[/tex]
D. [tex]5+(5+x)[/tex]



Answer :

Let's determine which expression is equivalent to [tex]\((k \circ h)(x)\)[/tex] given that [tex]\( h(x) = 5 + x \)[/tex] and [tex]\( k(x) = \frac{1}{x} \)[/tex].

The composition of functions [tex]\( (k \circ h)(x) \)[/tex] means we first apply [tex]\( h(x) \)[/tex] and then apply [tex]\( k \)[/tex] to the result of [tex]\( h(x) \)[/tex].

Step-by-Step Solution:

1. Evaluate [tex]\( h(x) \)[/tex]:
[tex]\[ h(x) = 5 + x \][/tex]

2. Substitute [tex]\( h(x) \)[/tex] into [tex]\( k \)[/tex]:
Since [tex]\( k(x) = \frac{1}{x} \)[/tex], we need to find [tex]\( k(h(x)) \)[/tex].
[tex]\[ k(h(x)) = k(5 + x) \][/tex]

3. Apply the function [tex]\( k \)[/tex] to [tex]\( 5 + x \)[/tex]:
Using the definition of [tex]\( k(x) \)[/tex],
[tex]\[ k(5 + x) = \frac{1}{5 + x} \][/tex]

So, the expression [tex]\( (k \circ h)(x) \)[/tex] simplifies to:
[tex]\[ (k \circ h)(x) = \frac{1}{5 + x} \][/tex]

Therefore, the expression equivalent to [tex]\( (k \circ h)(x) \)[/tex] is:
[tex]\[ \boxed{\frac{1}{5 + x}} \][/tex]