options: Build a function that models a relationship between two quantities.

Prove and apply trigonometric identities.

Construct and compare linear and exponential models and solve problems.

Understand the concept of a function and use function notation.

Analyze functions using different representations.

Model periodic phenomena with trigonometric functions.

Use functions to model relationships between quantities.

Interpret functions that arise in applications in terms of the context.

Interpret expressions for functions in terms of the situation they model.

Define, evaluate, and compare functions.

Extend the domain of trigonometric functions using the unit circle.

Build new functions from existing functions.
problem_activity: Task
Katy is told that the cost of producing $x$ DVDs is given by $C(x) = 1.25x + 2500.$ She is then asked to find an equation for $\frac{C(x)}{x}$, the average cost per DVD of producing $x$ DVDs.
She begins her work: $$\frac{C(x)}{x} =\frac {1.25x+2500}{x}$$ and finishes by simplifying both sides to get: $$C = 1.25+\frac{2500}{x}$$  Is Katy's answer correct? Explain.


correct_option_index: 3