MATH 1115 - SU24
Homework: Chapter 5

Question 6, 5.1.63

Part 1 of 2

Use [tex]\( f(x) = 5x - 3 \)[/tex] and [tex]\( g(x) = |x| \)[/tex] to evaluate each expression.

(a) [tex]\((f \circ g)(-3)\)[/tex]

(b) [tex]\((g \circ f)(4)\)[/tex]

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(a) [tex]\((f \circ g)(-3) = \square\)[/tex] (Simplify your answer.)



Answer :

Certainly! Let's solve each part step by step using the given functions [tex]\( f(x) = 5x - 3 \)[/tex] and [tex]\( g(x) = |x| \)[/tex].

### Part (a): [tex]\((f \circ g)(-3)\)[/tex]

The composition [tex]\((f \circ g)(x)\)[/tex] means we first apply [tex]\(g(x)\)[/tex], and then apply [tex]\(f\)[/tex] to the result.

1. Apply [tex]\(g(x)\)[/tex] to [tex]\(-3\)[/tex]:

The function [tex]\(g(x)\)[/tex] takes the absolute value of [tex]\(x\)[/tex].

[tex]\[ g(-3) = |-3| = 3 \][/tex]

2. Apply [tex]\(f(x)\)[/tex] to the result from [tex]\(g(-3)\)[/tex]:

Now we use the result [tex]\(3\)[/tex] from step 1 and plug it into the function [tex]\(f(x)\)[/tex].

[tex]\[ f(3) = 5 \cdot 3 - 3 \][/tex]

3. Simplify the result:

[tex]\[ f(3) = 15 - 3 = 12 \][/tex]

Therefore, [tex]\((f \circ g)(-3) = 12\)[/tex].

Answer:
[tex]\[ (f \circ g)(-3) = 12 \][/tex]

### Part (b): [tex]\((g \circ f)(4)\)[/tex]

The composition [tex]\((g \circ f)(x)\)[/tex] means we first apply [tex]\(f(x)\)[/tex], and then apply [tex]\(g\)[/tex] to the result.

1. Apply [tex]\(f(x)\)[/tex] to [tex]\(4\)[/tex]:

The function [tex]\(f(x)\)[/tex] is given by [tex]\(f(x) = 5x - 3\)[/tex].

[tex]\[ f(4) = 5 \cdot 4 - 3 \][/tex]

2. Simplify the result from [tex]\(f(4)\)[/tex]:

[tex]\[ f(4) = 20 - 3 = 17 \][/tex]

3. Apply [tex]\(g(x)\)[/tex] to the result from [tex]\(f(4)\)[/tex]:

Now we use the result [tex]\(17\)[/tex] from step 2 and plug it into the function [tex]\(g(x)\)[/tex].

[tex]\[ g(17) = |17| = 17 \][/tex]

Therefore, [tex]\((g \circ f)(4) = 17\)[/tex].

Answer:
[tex]\[ (g \circ f)(4) = 17 \][/tex]

This concludes the detailed step-by-step solution for both parts.