Functions and Readiness Checkpoint
A free Algebra II lesson from the “Functions and Notation” unit, with a worked example and practice problems including step-by-step solutions.
This checkpoint reviews Algebra II readiness skills around function notation, domain and range, transformations, inverses, and composition.
What you'll learn
- Evaluate and interpret functions
- Use domain, range, inverse, and composition ideas
- Connect notation to graph behavior
Worked example
Problem. If f(x) = 2x + 3 and g(x) = x - 5, find f(g(9)).
- Evaluate inside first: g(9) = 4.
- Now find f(4).
- 2(4) + 3 = 11.
Answer: 11
Practice problems
1. If f(x) = 4x - 1, find f(6).
Show solution
- Function Notation: First identify exactly what the question is asking: If f(x) = 4x - 1, find f(6).
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- 4(6) - 1 = 23.
- Check the result by substituting or estimating: the response should match 23 and make sense in the original problem.
Answer: 23
2. For points (1, 4), (2, 6), and (3, 6), the range is...
Choices: {4, 6} · {1, 2, 3} · {1, 4} · {2, 3, 6}
Show solution
- Domain and Range: First identify exactly what the question is asking: For points (1, 4), (2, 6), and (3, 6), the range is...
- For domain questions, identify input values that are allowed and watch for denominators, radicals, and context restrictions.
- Range uses output values.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: {4, 6}
3. For f(x) = 1/(x - 8), what value is excluded?
Show solution
- Domain and Range: First identify exactly what the question is asking: For f(x) = 1/(x - 8), what value is excluded?
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- The denominator cannot be zero.
- Check the result by substituting or estimating: the response should match 8 and make sense in the original problem.
Answer: 8
4. y = f(x + 2) shifts the graph...
Choices: Left 2 · Right 2 · Up 2 · Down 2
Show solution
- Transformations: First identify exactly what the question is asking: y = f(x + 2) shifts the graph...
- Use inverse operations to isolate the unknown, and keep both sides balanced at every step.
- Inside changes feel backward.
- Verify the selected choice by checking that it satisfies the original prompt and that the other choices fail the same test.
Answer: Left 2
5. If f(x) = x + 12, find f^-1(20).
Show solution
- Inverses: First identify exactly what the question is asking: If f(x) = x + 12, find f^-1(20).
- For function notation, treat the value inside parentheses as the input and carefully substitute it into the rule.
- Undo adding 12.
- Check the result by substituting or estimating: the response should match 8 and make sense in the original problem.
Answer: 8
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