Mathematics · Grades 9–12
Functions, domains and inverse reasoning · Revision card
A function assigns exactly one output to each allowed input.
Understand the idea
One input, one output
A function assigns exactly one output to each allowed input.
Restrictions matter
A formula may be undefined for some values.
Undo in reverse order
An inverse reverses a one-to-one function on its specified domain.
Worked examples
Which set of ordered pairs does not define y as a function of x?
Input 1 is assigned two different outputs.
{(1,2),(1,4)}
For f(x) = 3x − 7, calculate f(5).
3 × 5 − 7 = 8.
8
Explain without looking
- For p(x) = x² + 1, calculate p(−3) − p(3).
Further reading and review references
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Preview material · independent educational review required. Grade bands are approximate, not official curriculum alignment.