Composition of Functions and Modeling Answers

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A retailer is having a promotional sale for 35% off all items. There is a 7% sales tax added to the price. Which represents the situation, where x is the original cost of the item(s)?

A
f(x) = 0.35x represents the discount price and g(x) = 0.07x represents the price after taxes. The total price would be (f ∘ g)(x) = 0.35(0.07x) = 0.0245x.
B
f(x) = 0.65x represents the discount price and g(x) = 0.07x represents the price after taxes. The total price would be (f ∘ g)(x) = 0.65(0.07x) = 0.0455x.
C
f(x) = 1.07x represents the price after taxes and g(x) = 0.65x represents the discount price. The total price would be (f ∘ g)(x) = 1.07(0.65x) = 0.6955x.
D
f(x) = 1.07x represents the price after taxes and g(x) = 0.35x represents the discount price. The total price would be (f ∘ g)(x) = 0.35(1.07x) = 0.3745x.
168711

Which statements are true regarding the functions described? Check all that apply.

A
To get a volume of 100 cubic feet, the radius must be 2 feet.
B
The domain of V(h(r)) is restricted to values of r greater than 0.
C
The output of V is the input of h.
D
V(h(r)) = 3.5πr3
E
The volume depends on the radius of the cylinder.
168712

What is the selling price per widget as a function of the number of widgets produced, and what should the selling price be if 15 widgets are produced?

A
C(S(x)) = –0.196x2 + 100; $108.64
B
C(S(x)) = –0.196x2 + 100; $55.90
C
S(C(x)) = –0.14x2 + 140; $144.41
D
S(C(x)) = –0.14x2 + 140; $108.50
168713

Which statement describes function composition with respect to the commutative property?

A
Given f(x) = x² – 4 and g(x) = x – 3, (f ∘ g)(2) = –3 and (g ∘ f)(2) = –3, so function composition is commutative.
Option A
B
Given f(x) = 2x – 5 and g(x) = 0.5x – 2.5, (f ∘ g)(x) = x and (g ∘ f)(x) = x, so function composition is commutative.
Option B
C
Given f(x) = x² and g(x) = , (f ∘ g)(4) = 16 and (g ∘ f)(4) = 4, so function composition is not commutative.
Option C
D
Given f(x) = 4x and g(x) = x², (f ∘ g)(x) = 4x² and (g ∘ f)(x) = 16x², so function composition is not commutative.
Option D
168714

The compositions f(g(x)) and g(f(x)) of functions f and g are shown on the graph. Which statements describe the compositions? Check all that apply.

A
f(g(x)) = g(f(x)) for at least one value of x.
B
The composition of f and g is commutative.
C
f(g(0)) = 5 and g(f(–2.5)) = 5.
D
Both f(g(x)) and g(f(x)) have the same domain.
E
The graphs show that function composition is not commutative.

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