Unit 2 Review and Quiz
A free Precalculus lesson from the “Transformations and Combinations of Functions” unit, with a worked example and practice problems including step-by-step solutions.
This checkpoint makes sure students can move and combine functions before studying inverses. This lesson is part of Precalculus: Advanced Functions, so the emphasis is on interpreting behavior, choosing the right representation, and explaining the result clearly rather than memorizing isolated algebra moves.
What you'll learn
- Review transformations, symmetry, operations, and composition
- Choose the correct function, graph, or modeling tool from mixed prompts
- Explain why the selected method fits the problem
Worked example
Problem. Compared with y = f(x), the graph of y = f(x) + 3 shifts:
- Worked Example: First identify exactly what the question is asking: Compared with y = f(x), the graph of y = f(x) + 3 shifts:
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- Adding outside the function changes every output.
- Each output increases by 3.
- So the graph moves up 3.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: up 3
Practice problems
1. Unit review 1 (Vertical and Horizontal Shifts): Compared with y = f(x), the graph of y = f(x) + 3 shifts:
Choices: up 3 · down 3 · left 3 · right 3
Show solution
- Unit Review: First identify exactly what the question is asking: Compared with y = f(x), the graph of y = f(x) + 3 shifts:
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- Adding outside the function changes every output.
- Each output increases by 3.
- So the graph moves up 3.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: up 3
2. Unit review 2 (Reflections and Stretches): Compared with y = f(x), the graph of y = f(-x) is reflected across the:
Choices: y-axis · x-axis · line y = x · origin only
Show solution
- A negative sign INSIDE the function negates the input.
- Each point's x-value flips to its opposite, while y-values stay put.
- Flipping x-values reflects the graph across the y-axis.
Answer: y-axis
3. Unit review 3 (Combining Transformations): When several transformations appear at once, a useful first move is to:
Choices: separate the inside changes from the outside changes · multiply every constant together first · ignore the horizontal change · graph only the final answer
Show solution
- Inside changes (with x) act horizontally.
- Outside changes (the a and k) act vertically.
- Separating them keeps horizontal and vertical moves from mixing.
Answer: separate the inside changes from the outside changes
4. Unit review 4 (Even and Odd Functions): Which function is even?
Choices: f(x) = x^4 - 3x^2 · f(x) = x^3 - 1x · f(x) = x + 2 · f(x) = x^2 + 2x
Show solution
- An even function contains only even-power terms.
- x^4 - 3x^2 has all even powers, so f(-x) = f(x).
- The other choices contain an odd-power term.
Answer: f(x) = x^4 - 3x^2
5. Unit review 5 (Function Operations): If f(x) = 3x and g(x) = x, find (f/g)(4).
Show solution
- Unit Review: First identify exactly what the question is asking: If f(x) = 3x and g(x) = x, find (f/g)(4).
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- Find f(4) = 3(4) = 12.
- Find g(4) = 4, which is not zero.
- Divide: 12 / 4 = 3.
- Check the result by substituting or estimating: the response should match 3 and make sense in the original problem.
Answer: 3
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