Functions · Grade 8
In Grade 8 you learn: function notation.
A function is a rule that turns each input into exactly one output, written like f(x) = 3x + 1. Function notation makes it easy to talk about combining rules (composite functions) and undoing them (inverse functions).
Key facts
- f(4) means substitute 4 into the function f.
Worked examples
Example 1
f(x) = 2x² − 3. Find f(−2), and solve f(x) = 47.
Answer: f(−2) = 5; x = ±5