Find the inverse of a function, restrict the domain, and check by composition

Grade 11 Math Worksheet - Building Confidence

NameDate

Circle the best answer, or write your answer on the line.

  1. In a notebook, Ren has f(x) = 4x − 8, which multiplies by 4, then subtracts 8. Type one x-term and one number. What is f⁻¹(x)?

  2. On a puzzle card, f(x) = 5x − 15; f multiplies by 5, then subtracts 15. Zee needs f⁻¹(x) as one x-term and one number. What is it?

  3. On a worksheet, f(x) = x² + 3 for x ≥ 0. Ari wants the input that gives 52. What is f⁻¹(52)?

  4. In a notebook, Bo has f(x) = x² − 5, with x ≥ 0. What is f⁻¹(76)?

  5. Esme works in pencil with f(x) = (x − 2)² for x ≥ 2. What is f⁻¹(25)?

  6. On a puzzle card, f(x) = (x + 3)² for x ≥ -3. Jun needs f⁻¹(64). What is it?

  7. On a worksheet, f(x) = 3x − 4 and g(x) = (x + 4)/3. Kira tests whether g undoes f, starting with x = 5. What is g(f(5))?

  8. In a notebook, Luz checks f(x) = 2x + 7 against g(x) = x/2 − 7 at x = 3. What is g(f(3))?

  9. Milo works in pencil: f(x) = 4x + 1 and g(x) = (x − 1)/4. To test g as the inverse, what is g(f(6))?

  10. On a puzzle card, f(x) = 5x − 2 and g(x) = x/5 + 2. Noah checks one input, 4. What is g(f(4))?

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Find the inverse of a function, restrict the domain, and check by composition

Answer Key - Grade 11 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

  1. In a notebook, Ren has f(x) = 4x − 8, which multiplies by 4, then subtracts 8. Type one x-term and one number. What is f⁻¹(x)?

    (1/4)x + 2
  2. On a puzzle card, f(x) = 5x − 15; f multiplies by 5, then subtracts 15. Zee needs f⁻¹(x) as one x-term and one number. What is it?

    (1/5)x + 3
  3. On a worksheet, f(x) = x² + 3 for x ≥ 0. Ari wants the input that gives 52. What is f⁻¹(52)?

    7
  4. In a notebook, Bo has f(x) = x² − 5, with x ≥ 0. What is f⁻¹(76)?

    9
  5. Esme works in pencil with f(x) = (x − 2)² for x ≥ 2. What is f⁻¹(25)?

    7
  6. On a puzzle card, f(x) = (x + 3)² for x ≥ -3. Jun needs f⁻¹(64). What is it?

    5
  7. On a worksheet, f(x) = 3x − 4 and g(x) = (x + 4)/3. Kira tests whether g undoes f, starting with x = 5. What is g(f(5))?

    5
  8. In a notebook, Luz checks f(x) = 2x + 7 against g(x) = x/2 − 7 at x = 3. What is g(f(3))?

    -1/2
  9. Milo works in pencil: f(x) = 4x + 1 and g(x) = (x − 1)/4. To test g as the inverse, what is g(f(6))?

    6
  10. On a puzzle card, f(x) = 5x − 2 and g(x) = x/5 + 2. Noah checks one input, 4. What is g(f(4))?

    28/5