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), y = f(x) + 3 shifts:
- Worked Example: First identify exactly what the question is asking: Compared with y = f(x), 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 changes every output.
- Outputs increase by 3.
- That is a vertical shift up.
- 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), 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), 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 changes every output.
- Outputs increase by 3.
- That is a vertical shift up.
- 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 f(x), y = -f(x) is reflected across the:
Choices: x-axis · y-axis · line y = x · origin only
Show solution
- Unit Review: First identify exactly what the question is asking: Compared with f(x), y = -f(x) is reflected across the:
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- A negative outside changes y-values.
- Output signs flip.
- That reflects across the x-axis.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: x-axis
3. Unit review 3 (Combining Transformations): Read the transformations in y = -2f(x - 4) + 5.
Choices: right 4, vertical stretch by 2, reflect over x-axis, up 5 · left 4, vertical stretch by 2, up 5 · right 4, reflect over y-axis, down 5 · up 4, right 5, reflect over x-axis
Show solution
- Unit Review: First identify exactly what the question is asking: Read the transformations in y = -2f(x - 4) + 5.
- For signed numbers, track both distance from zero and direction so the sign of the answer makes sense.
- x - 4 shifts right 4.
- -2 outside reflects over the x-axis and stretches by 2.
- + 5 shifts up 5.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: right 4, vertical stretch by 2, reflect over x-axis, up 5
4. Unit review 4 (Even and Odd Functions): Which function is odd?
Choices: f(x) = x^3 - x · f(x) = x^2 + 1 · f(x) = x^3 + 2 · f(x) = x^4 - x^2
Show solution
- Unit Review: First identify exactly what the question is asking: Which function is odd?
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- Odd functions satisfy f(-x) = -f(x).
- Both x^3 and x change sign.
- So x^3 - x is odd.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: f(x) = x^3 - x
5. Unit review 5 (Function Operations): For (f/g)(x), if g(x) = x - 1, what value is excluded?
Show solution
- Unit Review: First identify exactly what the question is asking: For (f/g)(x), if g(x) = x - 1, what value is excluded?
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- The denominator function cannot be zero.
- Set x - 1 = 0.
- The excluded value is 1.
- Check the result by substituting or estimating: the response should match 1 and make sense in the original problem.
Answer: 1
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