GCSE · Functions

Function notationExam-style questions

Why f(x) is a machine's output, not a multiplication — evaluating f(3), reading f(x) = k as an equation to solve, and keeping inputs and outputs straight.

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11 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4Level 5
  1. 1
    g(x)=x2+1g(x) = x^2 + 1

    (a) Work out g(−3)g(-3)

    (b) Solve g(x)=50g(x) = 50
    Level 4 · 3 marksTry it
  2. 2
    f(x)=5−2xf(x) = 5 - 2x

    (a) Work out f(0.5)f(0.5)

    (b) Solve f(x)=xf(x) = x
    Level 4 · 3 marksTry it
  3. 3
    f(x)=x2−3xf(x) = x^2 - 3x

    (a) Work out f(5)f(5)

    (b) Solve f(x)=0f(x) = 0
    Level 4 · 3 marksTry it
  4. 4
    h(x)=12xh(x) = \dfrac{12}{x} for x≠0x \neq 0

    (a) Work out h(8)h(8)

    (b) Work out h(−4)h(-4)

    (c) Solve h(x)=5h(x) = 5
    Level 4 · 4 marksTry it
  5. 5
    f(x)=x2+2xf(x) = x^2 + 2x

    (a) Work out f(−3)f(-3)

    (b) Solve f(x)=15f(x) = 15
    Level 4 · 5 marksTry it